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Traffic backs up heading into the West Rock Tunnel (Heroes Tunnel) on the northbound Wilbur Cross Parkway in April 2017. |
Tunnel to Receive New Lighting
I had not heard any news about the West Rock Tunnel (Heroes Tunnel) project since 2021, so I sent an email to the DOT in November 2023 to ask about any project plans and received a reply. In particular, I asked about the lighting and also the concern about the potential for the crumbling concrete liner to peel away and land on a car.
With regard to the lighting, the reply was that the short term plan is to replace the current tunnel lighting with new LED lights because the existing fixtures are obsolete. The lights were replaced in January into early February 2024. I also asked if the light level would be adjusted at night so that motorists are not blinded going from a dark roadway into a bright tunnel and then back out into the darkness again. The DOT reply was that a lower light level at night is the plan.
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| New LED lights brighten the northbound tube of the West Rock Tunnel on Feb. 3, 2024. |
This is the link to the press release about the new lights:
As for the bigger picture, this was the reply:
"A short-term rehabilitation project, which will provide ventilation improvements and replacement of deteriorated sections of the concrete tunnel liner, is currently in preliminary design and anticipated to start in construction in 2026. We are also still evaluating the long-term traffic needs through the tunnel to see if a widening of the tunnel is needed. If we find that the tunnel barrels do not need to be widened to accommodate future traffic volumes, we will look to do more extensive rehabilitation or replace the tunnel liners entirely as part of the short-term rehab project that is in design. In the meantime, the Department’s inspectors continue to perform inspections annually and maintenance staff continues to remove loose concrete that they or the inspectors find."
With regard to the plans, this is the timeline:
"At this time, we anticipate having an updated project design that can be presented to the public in early 2024."
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The old-style lights are fully lit in this photo of the southbound tunnel shaft in February 2020. By the time of the lighting project in January 2024, more lights were extinguished than lit, leaving the tunnel in plenty of darkness. |
Tunnel Safety Needs Outlined in Report
The need to rehabilitate the tunnel shafts was discussed at length in this post I created in 2021.
Imagine driving through the West Rock Tunnel (Heroes Tunnel) and seeing a car burst into flames in front of you. What would you do to safely escape? What plan is in place to deal with a fire in the tunnel. In 2021, safety options are limited and emergency response is hampered by the tunnel’s current conditions, which do not meet modern safety requirements.
The state Department of Transportation (DOT) has postponed plans to overhaul the West Rock Tunnel (Heroes Tunnel) to meet modern standards, which might include blasting a third tunnel through the basalt ridge. Instead, the DOT announced more immediate plans to improve the safety and operations of the existing tunnels through the addition of these four systems: · Ventilation · Fire Detection and Fire Protection · Traffic Control · Emergency Egress These changes are necessary because the original ventilation and fire systems are non-functional. The fans in the tunnel air shaft (topped by the stone octagonal building located between the Regicides Trail and Baldwin Drive) were removed in the past, as was the traffic control system. The only emergency egress is along the 30-inch-wide sidewalk. An iron gate blocks the passage from one tube to the other. The changes would bring the tunnel into compliance with the National Fire Protection Association (NFPA) 502 Standard for Road Tunnels, Bridges and Other Limited Access Highways (2017). The information is contained in an October 2019 reported prepared by the engineering firm of CDM Smith for the DOT. The 78-page report is named Heroes Tunnel Project Ventilation Study, State Project 167-108, Technical Memorandum. The report contains graphics and maps to show the location of items discussed in the text. A related document is the 293-page Technical Memorandum Appendix. This document is described after the summary of the ventilation study. All tunnel reports may be found at the official state website: https://www.heroestunnelproject.com/HTProjDocs.php The follow information is taken directly from the report with some clarifications and explanations, as needed. In the original document, Section 1 is the Executive Summary and Section 2 is the Introduction. Section 3 discusses the existing conditions. Sections 4 and 5 provides the details as to why these safety systems are needed. Section 6 are the recommendations. There is a certain amount of repetition from one section to another. The introduction provides a brief overview of the tunnel and the rationale for the engineering study and is not excerpted here. Section 3: Executive Summary The upgrades to the Heroes Tunnel necessary to meet current NFPA 502 code requirements are presented in Section 6; a summary is provided below:
Ventilation System. Engineering analysis indicates that a pro-active system is required. The proposed system would consist of: · Six (6) unidirectional longitudinal 50,000 cfm jet fans per barrel to be automated, zone controlled and activated to respond to a fire incident in one of three (3) zones in the tunnel or due to CO levels exceeding the allowable threshold. · Two (2) 82,500 cfm exhaust fans at the top of the existing central shaft ventilation ducts to supplement the jet fans for a fire incident in the middle zone of a tunnel barrel · Reconstruction of the inlet ducts and vents at tunnel level, repair of the ventilation shafts, mounting the fans, and rehabilitation of the ventilation building at the top of West Rock Ridge · Electric control communication system for the automated operation of the ventilation system, including fire detection and carbon monoxide detectors Fire Detection and Fire Protection Systems. NFPA requires a dry fire protection standpipe system with connections to fire department water systems, a fire detection system, portable fire extinguishers, and an emergency two-way radio communication system.
Traffic Control. A means of stopping traffic at approach portals before entering the tunnel is required. Traffic control will also assist in egress requirements.
Emergency Egress. Emergency egress signage and lighting is required. As per NFPA 502, the new traffic control system that stops traffic from entering the tunnel during an incident allows the tunnel travel way to be used as an egress pathway. To meet emergency egress requirements the existing abandoned control room at the center of the tunnel will be reconstructed to function as an emergency egress cross passage between the two tunnel barrels.
Electrical Systems and Lighting. Complete replacement of the entire electrical system is needed based on new loading and the poor condition of the existing electrical systems. The replacement of the existing tunnel lighting system with center mounted LED fixtures that adapt to the tunnel lighting requirements of both daytime and nighttime illumination is proposed.
Structural Improvements to the Existing Tunnel. Mounting the new ventilation system, tunnel lighting, and standpipes to the existing tunnel ceiling and walls as well as the rehabilitation of the ventilation exhaust building at the top of the ridge, and the reconstruction of the existing control room into an egress cross passageway will be required. The leakage and cracking in the existing ventilation shafts will also be addressed.
Estimated Construction Cost = $20,150,000 (2021 construction season) * Estimated Project Cost = $25,020,000 (includes design and incidentals) * The reasons for these systems are detailed in the report. These excerpts highlight the essential information. According to NFPA 502, Heroes Tunnel is considered to be a Category C tunnel, due to the length of the tunnel exceeding 1000 feet. As a Category C tunnel, at least one manual means of identifying and locating a fire is required. A manual means of identifying and locating a fire consists of manual fire alarm boxes mounted in NEMA (National Electrical Manufacturers Association) Enclosure Type 4 (IP 65) or equivalent boxes at intervals of not more than 300 feet and at all cross-passages and means of egress from the tunnel. In addition, since no 24-hour supervision is provided throughout the tunnel, an automatic fire detection system is required in accordance with NFPA 502, section 7.4.7. Section 7.4.7 of NFPA 502 requires an automatic fire detection system installed in accordance with NFPA 72. Signals for the purpose of evacuation and relocation of occupants is not required, but automatic fire detection capable of identifying the location of a fire within 50 feet is required. A fire alarm control panel shall also be installed, inspected, and maintained in accordance with NFPA 72. Currently, no fire alarm system is installed. Additionally, two-way radio communication systems shall be installed in new and existing tunnel, where required by the authority having jurisdiction. Egress from the tunnel shall have a spacing between exits not exceeding 1000 feet, according to NFPA 502. Section 3: System Requirements and Existing Conditions 3.3.2 Existing Conditions Currently the tunnel does not meet emergency egress requirements since the central control room gates are locked and no fire door is installed this cannot be an egress point. Tunnel portals are 1200 feet apart, exceeding maximum egress pathway limits and the roadway cannot be egress parkway given no existing traffic control. Also existing 28-inch curbs do not meet minimum egress pathway width of 43 inches. 3.4 Fire Protection 3.4.1 Portable Fire Extinguishers 3.4.1.1 Standards, Codes, and Evaluation Criteria In addition to the fire alarm requirement, NFPA 502 requires portable fire extinguisher to be placed along the roadway in approved wall cabinets at intervals of no more than 300 feet. A minimum of a 2-A:20-B:C fire extinguisher spaced every 300 feet in an approved wall cabinet is required. The fire extinguisher mounting and cabinet must meet the requirements of NFPA 10. In order to ensure occupants have enough clearance to egress on the egress path, fire extinguisher cabinets shall be recessed into the tunnel walls. 3.4.1.2 Existing Conditions Presently there is no portable fire extinguishers in the tunnel. The original construction provided insets in the tunnel liner that held portable fire extinguishers speed at 150 feet. 3.4.2 Water-Based Fire-Fighting System 3.4.2.1 Standards, Codes, and Evaluation Criteria A fixed water-based fire-fighting system shall be mandatory in category C and Category D tunnels, according to NFPA 502. The goal of the water-based fire-fighting system shall be to slow, stop, or reverse the rate of fire growth or otherwise mitigate the impact of the fire to improve tenability conditions within the tunnel and enhance in the ability of first responders to aid in evacuation and/or protect the major structural elements of the tunnel. 3.4.2.2 Existing Conditions There is presently no fixed water-based fire lighting system installed in the tunnel barrels. 3.4.3 Fire Standpipe 3.4.3.1 Standards, Codes, and Evaluation Criteria According to NFPA 502, if the tunnel length is 300 feet or greater, a standpipe system shall be installed in accordance with the requirements of Chapter 10 of NFPA 502. The standpipe system shall be installed as a Class I system. Since it is subject to freezing, the standpipe shall be a dry standpipe system. The system shall be designed for a water supply capable of supplying the system demand for a minimum of 1 hour. Each independent standpipe system shall have a minimum of two fire department connections that are remotely located from each other. Standpipe systems shall be installed in accordance with NFPA 14 and inspected and maintained in accordance with NFPA 25. NFPA 502, chapter 10, allows a maximum travel distance of 150 feet between hose connections. The most remote standpipe shall have a flow of 500 GPM through the two most remote 2 ½ inch outlets, per NFPA 14. This results in a total of 5 standpipe connections per tunnel barrel. Figure 3-1 illustrates the proposed standpipes within the tunnel. In addition to standpipes, fire hydrants will need to be added near the tunnels. According to NFPA 14, section 6.4.5.4, fire department connections shall be located not more than 100 feet from the nearest fire hydrant. Currently, there are no fire hydrants within 100 feet of the tunnel portals. It is proposed to place two new hydrants on either side of the tunnels to allow for this code requirement to be met. Figure 3-2 illustrates the existing and proposed fire hydrant locations 3.4.3.2 Existing Conditions There presently is no fire standpipe system installed within the tunnel. 3.4.4 Emergency Ventilation System 3.4.4.1 Standards, Codes, and Evaluation Criteria Emergency ventilation shall not be required in tunnels less than 3,280 feet in length, where it can be shown by engineering analysis that the level of safety provided by a mechanical ventilation system can be equaled or exceeded by enhancing the means of egress, the use of natural ventilation, or the use of smoke storage, and shall be permitted only where approved by the authority having jurisdiction. The design of an emergency ventilation system shall be based on fire scenarios having defined heat release rate, smoke release rates, and carbon monoxide (CO) release rates. The design fires shall be sized based on a heat release rate provided by vehicle(s) and shall consider the types of vehicles that are expected to use the tunnel. 3.4.4.2 Existing Conditions Heroes Tunnel was originally constructed with ventilation shafts. The original ventilation system consisted of (4) 82,500 cubic feet per minute (cfm) fans. Two fans were used to serve the north tunnel and two were used to serve the south tunnel. The fans have since been removed and currently no ventilation system is in place. In 2009, CDM Smith conducted an inspection of the ventilation shaft and it was found that the ventilation structure appears to be in fair to good condition. Some leaking construction, cracks, spalls (flakes of concrete that are breaking away) and scaling (surface flaking and peeling) was found. 3.5.2 Existing Conditions The existing structural system (tunnel liner) that provides permanent support to the rock mass is reinforced concrete, with #4 and #5 reinforcing bars at typical spacing, and with 2-in clear cover to reinforcement. During construction, where the rock mass had to be supported prior to the tunnel liner being installed, steel sections, typically W8X31 with blocking, were utilized. Without physical testing of the concrete liner to ascertain material properties and assess material condition and without performing computational fluid dynamic (CFD) modelling and numerical structural analysis that accounts for material property changes, it is difficult to quantify performance of the existing structural elements subjected to elevated temperatures to meet current NFPA 502 requirements. At the time of construction of the Heroes Tunnel, standards such as those currently established by the NFPA for road tunnels did not exist. Therefore, it is likely that the tunnel structural elements were not designed to meet any requirements to prevent collapse due to fire and their state of deterioration could further limit these elements capability to withstand these temperature exposures. 3.6.1.1 Tunnel Traffic Control According to NFPA 502 Section 7.6, all road tunnels must provide a means to stop approaching traffic in response to emergency conditions. Furthermore, tunnels longer than 800 feet (applicable to Heroes Tunnel) must provide means to stop traffic from entering the tunnel, control traffic already within the tunnel, and also clear traffic downstream of the site of the emergency. Specifically, the following extracted requirements are defined under Section 7.6.2: 1. Direct approaches to the tunnel shall be closed following activation of a fire alarm within the tunnel. Approaches shall be closed in such a manner that responding emergency vehicles are not impeded in transit to the fire site. 2. Traffic within the tunnel approaching (upstream of) the fire site shall be stopped prior to the fire site until it is safe to proceed as determined by the incident commander. 3. Means shall be provided downstream of an incident site to expedite the flow of vehicles from the tunnel. If it is not possible to provide such means under all traffic conditions, then the tunnel shall be protected by a fixed water-based fire-fighting system or other suitable means to establish a tenable environment to permit safe evacuation and emergency services access. 4. Operation shall be returned to normal as determined by the incident commander. Section 7.16 Emergency Exits requires that exits for protection of tunnel occupants not exceed 1,000 feet. The length of Heroes Tunnel is approximately 1,200 feet with no internal means of egress. Should an internal egress path be installed between barrels for occupants to egress from one barrel to another barrel during an emergency situation, it is essential to provide traffic control to ensure occupancy safety. It would not be safe for occupants to egress into the other tunnel barrel where traffic is moving at full speed. The report details the technical specifications for exit signs, exit path marking, and sign lighting. There should also be signs and announcements that briefly state the problem and what people should do, i.e., fire in the tunnel and walk to the exits. 3.6.2 Existing Conditions Currently, no elements are in place to meet the aforementioned requirements set forth for traffic control in or around the tunnel. Based on the traffic control requirements, the following critical needs were identified: · Install measures to close tunnel entrances to additional traffic while allowing access to emergency vehicles. · Install measures to stop upstream traffic prior to the fire site until it is safe to proceed as determined by the incident commander. · Provide means downstream of incident site to expedite flow of vehicles from the tunnel. Section 3 · System Requirements and Existing Conditions 3-12 · Define and implement system to allow incident commander to return operations to normal. · Install additional egress point within tunnel to meet 1,000 feet egress maximum spacing requirement. · Install emergency signage and markings to facilitate occupant egress. · Install upstream warning devices in advance of vehicle queues and alternate routes · It should be noted, however, that the original construction of the tunnel did include emergency management features such as traffic lights with flashers. Electrical System Condition ratings were determined through review of existing plans, inspection reports, and a site visit. During the site visit, the southbound barrel was inspected. It is assumed equipment in the northbound barrel is in similar condition. Overall, the power distribution is in serious condition due to the ATS (automatic transfer switch) being unreliable, resulting in the possibility of a loss of power to the tunnel. The lighting system is also in serious condition. Light quality is poor and insufficient. The gas and fire alarm systems are nonexistent and are required by code. 3.7.2.1 Power Distribution The electrical system at the Heroes Tunnel had its last major upgrade in 1984. The electrical service for the tunnel is 600 Amp, 480/277 Volt, 3-phase, 4-wire, connected to two separate utility sources, which are tied through an ATS. CT-DOT has indicated that the ATS has not been used in many years and may be non-functional. Note that the nighttime lighting panelboard has a circuit breaker which was used to power a panelboard for the equipment in the control room (lights, fans, receptacles, heaters). The fans, transformer, panelboards, heaters, and other equipment were removed from the control room after they were no longer functioning or considered unsafe. From the site visit conducted by CDM Smith it appears the only remaining functional electrical equipment within the tunnel itself are the lighting fixtures. Most components of the power distribution system are in poor to serious condition and beyond their useful life. If power from the Manila Avenue feed is lost and the unreliable ATS fails to operate, the tunnels could be left without lighting, which is critical to life safety. The panelboards and other equipment within the pedestal cabinet should be considered priority. The conduit system throughout the facility is in fair to poor condition, with noticeable sagging, corrosion, and cracking. Exposed PVC conduit exists in the tunnels, which is a violation of NFPA 502 Paragraph 12.3.2(2) due to the emission of toxic fumes in event of a fire. Any exposed conduit installed as part of tunnel rehabilitation shall be metallic unless otherwise permitted. 3.7.2.2 Lighting Record drawings indicate that each tunnel contains 149 linear fixtures mounted on the center of the ceiling. The barrels contain three different types of lighting fixtures, all operating at 480 Volts. The fixtures at the entrance of each barrel contain two 4 foot, 180 watt low-pressure sodium (LPS) lamps, with some fixtures also containing an additional 55 watt lamp for nighttime lighting. The fixtures at the exit side of each barrel contain a single 180 watt lamp, with some containing the 55 watt nighttime lamp as well. The daytime fixtures are controlled by the photocell above the pedestal cabinet, as described in the power distribution section. Many lighting fixtures are “out,” or non-functional, with either the lamps or ballast having reached their point of failure. Covers are missing on many fixtures, thereby voiding any environmental rating the fixtures originally carried. Luminance (candela/m2) and illuminance (foot-candle) levels in both tunnels are insufficient and do not meet IES standards. The LPS fixtures also provide poor color rendering, resulting in objects not appearing the same color as when they are illuminated by a natural light source. These factors combine to create an environment where drivers may not be able to properly respond to maneuvers and incidents. There are no exit signs or egress lighting fixtures or markings within the tunnel. The conduit system associated with the lighting is in fair to poor condition. Moderate corrosion is visible, and many junction boxes are missing covers, exposing the wiring. The lighting system is overall in serious condition and should be replaced and upgraded as soon as possible. 3.7.2.3 Gas and Fire Alarm Systems According to record drawings, the barrels were previously equipped with a carbon monoxide (CO) detection system. This system is no longer present. There are currently no gas or fire alarm systems in the tunnels. 3.8 Emergency Response Plan 3.8.1 Standards, Codes, and Evaluation Criteria The Emergency Response center in Chapter 13 of NFPA 502 out-lines the planning, coordination and cooperation requires with all participating agencies to fully prepare, train and respond to emergency incidents within the tunnel. The development of an emergency respond plan that anticipates the various emergency incidents that could occur at this facility and identifies the participating agencies and their responsibilities needs to be developed and submitted for approval to the authority having jurisdiction. This plan is dependent on the firefighting equipment to be installed within the tunnel and the available equipment of the responding agencies. Liaison personnel from participating agencies shall be noted in the response plan and updated as required with the list reviewed for it to be current at last and every three months (13.6.3). Training and drills are required to be conducted at least twice a year (13.8.4). 3.8.2 Existing Conditions There is presently not an emergency response plan prepared for an incident at the tunnel. Coordination of service responders and responder readiness for an incident at the tunnel have not been determined. Comment: Section 4 of the report is an engineering analysis testing scenarios for a fire in one tube in the tunnel. Section 4: Engineering Analysis 4.5.1 Power Distribution Being classified as Category C according to NFPA 502, the tunnel is required to have an emergency power system in accordance with NEC (National Electric Code) Article 700, which outlines the types of systems which may be acceptable as emergency power sources and the requirements for each. Types of emergency power systems include but are not limited to generator sets, storage batteries (unit-mounted or centralized), separate services, and uninterruptible power supplies (UPS). Paragraph 12.4.1 of NFPA 502 indicates the systems required to be connected to the emergency power system. They include: Emergency lighting· Tunnel closure and traffic control · Exit signs · Emergency communication · Tunnel drainage · Emergency ventilation · Fire alarm and detection · Closed-circuit television or video · Fire fighting
Reusing the existing electrical equipment in the pedestal cabinet to feed new loads is not feasible. There is insufficient space and capacity to accommodate the recommended ventilation equipment. There is also not enough space for new lighting control equipment which would increase system performance and manageability. New electrical equipment and a different power distribution system arrangement are required for code compliance. A new building will be required to house the new electrical distribution equipment. Existing equipment shall be demolished or abandoned in place as new equipment is placed into service. 4.5.1.1 Proposed Electrical Distribution The ventilation study has resulted in a total of 8 fans (6 longitudinal jet fans, 2 exhaust fans) being recommended for each tunnel to maintain tenability. An emergency motor control center (MCC) is proposed to house the motor starters for the reversible fans and to power the other emergency loads (lighting, traffic control, communications, fire alarm, and CCTV). Each bus (a type of electrical junction) will supply about half of the emergency loads in each barrel during normal operating conditions, providing even further assurance that life safety does not depend on any one of the three (two utility, one generator) power sources. Note that the entire tunnel lighting system shall be considered part of the emergency system and will be fully backed up. 4.5.2.2 Design Considerations When drivers approach a tunnel during the daytime they are adapted to exterior light levels which are higher than those in the tunnel. The light distributed by interior lighting fixtures cannot compete with the sun or sky, but they can give drivers’ eyes time to adapt. Lighting within the threshold zone must provide drivers with luminance that is sufficient for detecting conflicts. If the entrance is too dark, a “black hole effect” is created, and drivers will slow down prior to reaching the portal. Light at the entrance must be bright enough to instill a sense of safety. As drivers’ eyes adapt further in the threshold zone and in the transition zone, light levels can be safely reduced, conserving a significant amount of energy. Selection of type and configuration of fixtures must be performed in conjunction with the specification of a lighting control system capable of dimming fixtures according to their zone. A control system capable of measuring the light levels at the portals and adjusting fixture lumen output accordingly is also recommended. At night, drivers’ eyes are already adapted to low light levels and a constant average pavement luminance is recommended throughout the tunnel. Also recommended at night is pole-mounted approach and exit lighting up to one SSSD that establishes levels no less than one-third that of the interior levels. The lighting control system must be capable of responding to the decreased light levels as night approaches and adjust the interior and exterior light levels accordingly. A key basis for design of a tunnel lighting system is the required pavement luminance, which is based on the tunnel’s shape, orientation, surroundings, materials of construction, posted speed, and average annual daily traffic (AADT). The OSTA approved speed limit is 55 mph. The average annual daily traffic is approximately 77,000 vehicles. The orientation of the tunnel is nearly southwest to northeast. The presence of West Rock Ridge above and about the tunnel provides some shielding from the sky and sun. Thus, Heroes Tunnel is considered a “mountain tunnel.” 4.5.2.3 Criteria and Proposed Lighting System For each barrel, a linear fixture arrangement mounted on the ceiling center line is recommended. Fixtures shall be light-emitting diodes (LED), as LED lighting fixtures have superior efficacy (lumens/watt) and useful life (>100,000 hours) when compared to other light sources. Fixtures shall emit ALD-NC (counter-beam) distribution. During the daytime, the lighting system shall provide the highest luminance within in the threshold zone near the tunnel’s entrance, and the system shall provide incrementally reduced light levels further into the threshold zone and in the transition zone. A total of 130 fixtures is proposed for the interior of each barrel. In the graphics on page 4-43 of the report, daytime fixtures are shown in black, green, and pink. Nighttime fixtures are shown in red and blue, with red also denoting emergency fixtures. Nighttime fixtures shall only operate at night. Daytime fixtures near the tunnel entry are spaced 6.5’ on-center, whereas daytime fixtures near the exit are spaced 40’ on center. For each barrel, the approximate lighting load is 43 kW during the day and 2 kW at night. Nighttime lighting is recommended along the roadway within one SSSD of each tunnel’s entry and exit portals. This can be accomplished with four roadside pole-mounted fixtures at each approach and exit. 4.5.2.4 Lighting Control System Control equipment is required to switch and dim the tunnel LED lighting. Generally, a lighting control panel is required, and control wiring is run alongside the power conductors to the drivers at the LED fixtures. Some methods include using 0-10V analog wiring or using a digital addressable lighting interface (DALI), which utilizes data highway cable. The lighting control scheme should be able to dim the lighting fixtures according to zone and circuit. It is recommended for the lighting control panel to be able to be programmed for multiple scenes (e.g. daytime, nighttime, maintenance). It is recommended for the system to be capable of receiving remote signals from the maintenance operators/technicians to change the lighting system settings as required. Whether the signal is wireless or hardwired back to a control facility shall be decided during detail design. Since the luminance at the tunnel portal varies with weather, time of day, and time of year, it is recommended that a luminance photometer be installed one SSSD from each entry portal. The photometer measures the light around the portal and signals the lighting control panel(s) to respond accordingly by adjusting the light levels within the tunnel. It may be feasible for the photometer be installed on the same truss as the traffic information display. Illuminance photometers are sometimes installed within tunnels as well. Because Heroes Tunnel is relatively short, internal illuminance photometers are not necessary. 4.5.2.5 Emergency and Egress Lighting In addition to the emergency criteria listed in the table above, NFPA 502 also dictates in Paragraph 12.6.5 that “there shall be no interruption of the lighting levels for greater than 0.5 second.” It is already proposed to back up the entire lighting system on emergency power. However, there should be another level of redundancy installed to ensure the tunnel is never without lighting. The fixtures shown in red in the proposed layout (spaced 80’ on-center) should be placed on UPS in case of the rare failure of the other power sources. The recommended UPS lighting load is only about 500 Watts for each tunnel and would ensure that the tunnels are not without lighting. Paragraph 7.16.1.2 of NFPA 502 states that “reflective or lighted directional signs indicating the distance to the two nearest emergency exits shall be provided on the side walls at distances of no more than 82’.” Exit signs are required at the points of egress. It is recommended for each of these signs to be internally illuminated, and consideration should be given to putting them on UPS power. 4.5.3 Fire Alarm System Paragraph 7.4.2 of NFPA 502 requires either 24-hour supervision of the tunnel or installation of an automatic fire detection system. Because longitudinal and exhaust fans are required in event of a fire, an automatic fire alarm detection system is recommended to ensure prompt and precise response to a fire. Paragraph 7.4.8 requires a fire alarm control panel (FACP) to be installed, inspected, and maintained in accordance with NFPA 72. The FACP may be located in the recommended new electrical building. During detailed design, consideration can be given to whether the FACP communicates to dispatch directly or through systems at the control facility. Paragraph 7.4.6.1 of NFPA 502 requires manual fire alarm boxes to be “installed at intervals of not more than 300 feet and at all cross-passages and means of egress from the tunnel.” Heroes Tunnel requires approximately 12 manual fire alarm boxes, the exact number shall be confirmed during detailed design. Paragraph 7.4.7.4 of NFPA 502 requires automatic fire detection systems to be capable of identifying the location of a fire within 50 feet. CCTV cameras may be used as part of the automatic fire detection system, but it is not recommended. The precision required to properly operate the ventilation system may not be provided with such a system. Instead, spot-type heat detectors are recommended to be installed every 50 feet, and they “shall be zoned to correspond with the tunnel ventilation zones where tunnel ventilation is provided,” in accordance with NFPA 502 Paragraph 7.4.7.6. The location of the fire shall dictate the specific response of the ventilation system, signaling the motor control equipment as required. Linear type heat detector may also be used. Fiber optic-type linear heat detector cables may be installed in lieu of traditional metallic linear detectors. Note that per NFPA 502 Paragraph 7.4.7.2, signals for the purpose of evacuation and relocation of occupants within the tunnel are not required when an automatic fire detection system is properly installed and approved. Carbon monoxide samplers and analyzers will be required for each tunnel, and they will coordinate with the alarm signaling system and the ventilation system control equipment. Carbon monoxide detection equipment shall be connected to an emergency power system in accordance with NFPA 72. Exact location of the equipment will be selected during detailed design. 4.5.4 Miscellaneous Electrical 4.5.4.1 Closed-Circuit Television (CCTV) The Department may elect to install cameras on the interior and exterior of each tunnel. Required network and server equipment may be installed in the new electrical building, and a monitoring station may be installed at the existing control facility. 4.5.4.2 New Electrical Building The proposed new building is required to house the new electrical equipment. Installing the equipment in pedestal cabinets and weatherproof enclosures is not practical due to the size and extent of equipment required. The location of the building shall be selected during detailed design, keeping in mind possible tunnel rehabilitation/replacement and West Rock Ridge State Park. The CT-DOT District Office (on Pond Lily Avenue in New Haven, adjacent to the parkway on the northbound side) is close enough to the tunnel that placing a new electrical building adjacent to the CT-DOT District Office would result in only modest conductor upsizing to prevent voltage drop when compared to that required for an electrical building directly next to the tunnel. 4.5.4.3 Miscellaneous Loads, Communications Network equipment shall be provided within the new electrical building to communicate with the necessary authorities. Separate communication channels will be required for certain legally required signals and other signals. Power and communications will be required for the lane-use control signal displays. As a note, power may be brought back to the ventilation building at the top of the ridge for lighting and receptacles if required. Section 5: Engineering Analysis Results 5.1 Means of Egress Evacuation Model Pathfinder, a model used to evaluate evacuation, demonstrated that if occupants behave based on the assumption that people move away from the fire, people can safely egress the space with the ventilation configuration being proposed. If a fire is reported in the middle of the tunnel, the exhaust fans will activate and the bi-directional fans will blow the smoke toward the center exhaust shaft. With the fire in the center, people begin to egress toward the exit ends of the barrel toward safety. If a fire is to occur on either end of the (the entrance or exit of the tunnel barrel) people will begin to egress toward the open end of the barrel that is not blocked by the fire and egress through the center of the tunnel barrel into the other barrel where no fire is present. This new egress corridor being proposed in the center of the tunnel is to meet the code requirement in NFPA 502 for travel distance. During this egress scenario it is important that a traffic control system is implemented to allow for occupants to safely enter the other tunnel barrel and exit safely into traffic. With bidirectional fans activated, occupants are able to egress from the tunnel before tenability becomes untenable. It is assumed that occupants in the direct vicinity of the fire, where noticeable fire conditions are present, will egress from the area before it becomes untenable. The tunnel, excluding the fire area in the direction of smoke exhaust, remains tenable for the length of the simulation, 20 minutes, as long as the fans and exhaust operate properly and remain active during the length of the scenario. 5.2 Carbon Monoxide (CO) 5.2.1 CO Scenario 1 Results The results from the first CO scenario verified that some type of ventilation system would be required to maintain the CO within the space below a level of 50 ppm. This scenario ran for a time of two hours and at a time of 3600 seconds, one hour, the average carbon monoxide (CO) level at 6.56 above the ground is 85 ppm. At the end of the simulation the average the average carbon monoxide (CO) level at 6.56 above the ground is 97 ppm. These exceed the threshold of 50 ppm. It was from this scenario that it was determined that exhaust fans would be required to maintain tenability levels within the tunnel. 5.2.2 CO Scenario 2 Results Scenario 2 included the use of the center ventilation shaft. By utilizing the center ventilation shaft and exhausting a total of 165,000 cfm the tunnel remained tenable for the occupants below a level of 50 ppm of CO. A total of two 82,500 cfm fans were used to reduce the CO within the tunnel. In addition, Clarage (a manufacturer of heavy duty industrial fans) fans were also tested to determine if they could be used to maintain tenability below 50 ppm for CO. It was determined that a total of 6 fans, per tunnel barrel, at 50,000 cfm could also be used to maintain tenability within the tunnel. The fans were blowing in the direction of traffic and the fans pushed the CO out of the tunnel and kept the tunnel space tenable for the occupants. There is 207 feet between each fan. 5.2.3 CO Scenario 3 Results Scenario 3 was evaluated based on the same assumptions as scenario 2, but a new assumption was included that occupants would shut off their vehicles to reduce the amount of CO being added to the tunnel. Occupants would be notified via a message provided in the tunnel to shut off their vehicles. This scenario was found to not only reduce the amount of carbon monoxide (CO) being injected into the space, but overall reduce the amount of carbon monoxide (CO) in the space due to the help of the exhaust fans. This scenario was able produce a carbon monoxide (CO) level that is maintained below the threshold of 50 ppm. In addition, Clarage fans could too be used for this scenario and it would maintain tenability. Once the cars are shut off, the CO stops, and eventually all the CO in the space is pushed out by the 6 Clarage fans placed throughout the tunnel 5.3 Fire Scenario Modeling Results 5.3.1 Fire Scenario 1 Results Scenario 1 was used to validate that an exhaust system is required to maintain tenability throughout the tunnel. The simulation demonstrated that without a system in place to exhaust the smoke, the tunnel filled in roughly 320 seconds, with the fire located on the South end. Based on the fire modeling results of this scenario it is concluded that an exhaust system will need to be present in order to maintain tenable conditions throughout the tunnel. 5.3.2 Fire Scenario 2 Results Based on the fire modeling results of scenario 2, the exhaust fans were sized to keep the tunnel barrel at tenable conditions, until occupants are able to egress the space. An exhaust fan size of two 82,500 cfm fans was used to maintain tenability within the tunnel for occupants to egress. With the fire being located at the south end of the tunnel, the exhaust shaft located in the center seemed to pull the smoke throughout the entire half of the tunnel resulting in untenable conditions for a large portion of the occupants. Based on these results, it was concluded that a fire located on the south end of the tunnel would be the worst-case scenario. This scenario determined that the exhaust shaft alone would not keep the conditions tenable for the occupants during egress and an alternative solution is required. 5.3.3 Fire Scenario 3 Results Based on the fire modeling results of scenario 2 the exhaust shaft alone is not able to maintain tenable conditions. The following ventilation designs were analyzed in the model to determine what size ventilation fans could be used to maintain tenability during the fire scenarios. · Use of only two central shaft ventilation fans each with 82,500 cfm capacity · Use of six (6) longitudinal 50,000 cfm jet fans acting in a single direction without the use of the central ventilation shaft · The use of six (6) unidirectional longitudinal 50,000 cfm jet fans supplemented by the two central ventilation shaft fans. None of these options met tenability requirements. The alternative that did meet tenability requirements was an automated ventilation system that combined the central ventilation shaft fans with a total of six (6) bi-directional fans in each tunnel barrel with the fans blowing in the direction of the fire. Since the fire was located on the lowest end of the tunnel, the fans would blow towards the low end of the tunnel, blowing the smoke out of the barrel to maintain tenable conditions for occupant egress. Section 5 below discusses the suggested solution to maintain tenability for all fire scenarios. This scenario resulted in an egress time of 240 seconds, without any delay time assumed, and therefore would require tenability limits within the space to be maintained for a time exceed 240 seconds. This 240 second travel time included occupants egressing through the center exit corridor, as this is a requirement of NFPA 502. The 240 second travel time was the total time it took for all occupants to egress the tunnel. 5.4 Electrical Systems Comprehensive replacement of the electrical systems is recommended because the systems are either not code compliant or well beyond their useful life. It is recommended that two utility electrical services are provided to the tunnel and that they are both operational under normal operating conditions. Both utility services shall supply a number of normal and emergency loads through normal distribution power panels and an emergency motor control center. The emergency motor control center shall be main-tie-main configuration and shall power all emergency loads required by code. A full list of code-required emergency loads is included in Section 4. It includes but is not limited to tunnel ventilation, lighting, and gas and fire alarm systems. Each MCC bus shall power approximately half of the electrical loads within each barrel. It is recommended for each utility service to be connected to an ATS that has a generator set as the emergency power source. In case of a utility service failure, the emergency generator shall power the emergency loads normally supplied by that utility service. The tie circuit breaker at the MCC allows for flexibility of power source selection during maintenance periods and even during normal operating periods. Because of the tunnel’s geometry, a centerline ceiling mounted lighting system is recommended. LED lighting systems provide optimal light distribution, efficiency, and controllability. The type, spacing, and lumen output of the lighting fixtures shall be controlled according to their location within the tunnel, the time of day, and the specific exterior lighting conditions at any given point during the day. Counter-beam lighting is recommended, as it is most efficient in distributing light that allows motorists to properly respond to conflict. It is recommended for the entire tunnel lighting system to be backed up on emergency power. Select lighting circuits shall be backed up on UPS (uninterruptible power supplies) so that it is virtually guaranteed that the tunnel is never without illumination. A lighting control system consisting of control cabinets and local fixture controllers is recommended to control the output of the fixtures. A luminance photometer shall be provided at the approach to each tunnel to measure the amount of light present and allow the control system to control output accordingly. Internally illuminated egress signs shall be placed throughout the tunnel according to the distance required by code and at all points of egress. A fire alarm system shall be installed within the tunnel in compliance with code and in coordination with the recommended ventilation system. Manual fire alarm pull boxes and spot type heat detectors shall be installed at code-required distances. Carbon monoxide probes and analyzers are recommended to be installed. Activation of gas or fire alarm detection devices shall result in activation of the ventilation system according to the location of detection. Alarms and signals shall be communicated with the appropriate parties (e.g. Fire Department, CTDOT) through either hardwired or wireless signals as required. A building or other climate-controlled structure is recommended to house all the power distribution, control, and networking equipment.
Section 6: Recommendations 6.1 Fire Detection 6.1.1 Fire Alarm System Fire alarm systems are intended for life safety and should be design, installed, and maintained to provide indication and warning of abnormal unsafe conditions. This system should alert occupants and summon appropriate aid in adequate time to allow for occupants to travel to a safe space. The fire alarm system should be part of the life safety plan that includes a combination of prevention, protection, egress, and other features particular to that occupancy. Instead of smoke detection throughout the tunnel, Gas detectors are suggested in order to monitor tenability throughout the space. It is our recommendation that once the gas detectors reach a specific threshold (such as 40 ppm of CO) a signal would be sent to the ventilation system to prevent the space from reaching great than 50 ppm of CO within the space. Gas detectors, linear heat detection, or flame detection systems will be used for the fire alarm system. Additionally, manual means of detection are suggested, such as manual fire alarm pull station every 300 feet. This would be beneficial for occupants egressing the tunnel to notify others of an evacuation emergency. Once the pull station is activated strobes placed throughout the tunnel would activate to notify others to begin evacuation. This suggestion is a method to get occupants to begin evacuating the tunnel earlier. 6.2 Means of Egress In order to meet the requirements of NFPA 502 and to allow for safe evacuation for occupants during an emergency situation, it is recommended to add an egress corridor from one tunnel barrel to the other. See Figure 6-1 illustrating the layout being proposed and the alternations required to the existing central control room to form an egress corridor. The corridor shall have fire doors on both sides of the egress corridor to provide adequate separation and with proper traffic control installed the travelway can be used as an egress pathway. 6.3 Fire Protection 6.3.1 Automatic Fire Sprinkler System It is our recommendation, based on the results from the fire modeling, that no automatic fire sprinkler system will need to be provided throughout the tunnel. With the other fire safety measures in place, such as a smoke ventilation system, an additional egress route, and adding standpipes that the tunnel remains tenable for the occupants during the time of egress. 6.3.2 Smoke Ventilation System After running multiple CO testing using FDS, it is our recommendation to use Clarage fans once the CO level reaches 40 ppm. If after 5-10 minutes the CO level with the tunnel is not reduced, it is recommended to activate the exhaust to ensure the CO level does not reach 50 ppm and cause harm to the occupants within the tunnel. These fans will be activated by gas detectors located throughout tunnel. Based on the worst-case scenario without ventilation, a system is required to maintain tenability conditions throughout the tunnel. It is proposed to incorporate a ventilation system to maintain the tunnel at tenable conditions for occupants. Based on the worst-case fire modeling results, in a total ventilation capacity of 165,000 cfm (two 82,500 cfm fans or four 41,250 cfm fans) are suggested. In addition to the exhaust shaft being used, bi-directional jet fans placed at the ceiling of the tunnel are also being proposed. The ventilation system being proposed is to be located in the center of the tunnel using the existing ventilation shafts in addition to the bi-directional jet fans being proposed consists of 6 fans per tunnel barrel at 50,000 cfm per fan, resulting in a total of 12 jet fans. The fans are spaced approximately 207 feet apart. In order to ensure that the ventilation system and jet fans operate correctly, our recommendation is to complete concrete surface repairs to spalls and cracks within the ventilation shaft and grout the joints to eliminate the contact between ventilation shaft and groundwater. This will reduce the effect of the freezing and thawing of groundwater and eliminate the icicles during winter, which could result in damage to newly installed fans. Also, we recommend separating the two tunnels by closing off the wall that connects the two tunnels to allow complete separation between the two. This will allow the ventilation shaft and jet fans to properly remove the smoke within the barrel. The fire models were model as separate spaces, similar to if a wall was added to prevent smoke and air from moving back and forth between barrels. By completing the fire modeling with multiple scenarios, it was determined that an alternative would need to be considered. A zoning method is proposed to help maintain tenability throughout the tunnel. Our proposed solution is to have bidirectional fans and update the existing shaft with new exhaust fans to maintain tenability. If the fire is detected on the lower south end of the tunnel, the ventilation fans shall be programmed to blow towards the left end. If the fire is detector on the upper north end of the tunnel, the ventilation fans shall be programmed to blow toward the right end. The exhaust would not activate in these scenarios. If a fire was located in the center of the tunnel the exhaust would activate and the ventilation fans would blow towards the exhaust shaft. 6.3.3 Fire Department Connections (FDC) In order for the fire department to fight a fire within the tunnel standpipes need to be installed, as required by NFPA 502, every 275 feet. The system shall be installed in accordance with NFPA 14 and inspected and maintained in accordance with NFPA 25. With the water supply available for the fire department, controlling a fire within the tunnel will be a manageable task. Currently, three fire hydrants are near the location of the tunnel, but none are within 100 feet of the tunnel entrance or exit points. This would result in limited resources for the fire department. Adding a total of 5 standpipe connections within each tunnel barrel, to meet NFPA 502 and NFPA 14 code requirements is proposed. A layout of the proposed standpipe locations is illustrated previously in Figure 3-1. The standpipes are spaced with a travel distance of not greater than 275 feet between each standpipe connection. Each standpipe location requires two fire department connections. In addition to the standpipes, two new fire hydrants are proposed for the tunnel. In order to meet the requirements of NFPA 14, section 6.4.5.4, a fire department connection shall not be located more than 100 feet from the nearest fire hydrant. With the current layout of the fire hydrants, this requirement cannot be met. We propose adding two new fire hydrants, one to each side of the tunnel.
6.4 Fire Protection of Structural Elements The Heroes Tunnel is a Category C facility that is subject to the specific requirements stipulated in NFPA 502, Section 7. Concrete has excellent inherent fire-resistivity properties. However, concrete structures must still be designed for fire effects. Structural components need to withstand dead and live loads without collapse; rise in temperature causes a decrease in the strength and modulus of elasticity for concrete and steel reinforcement. In addition, fully developed fires cause expansion of structural components and the resulting stresses and strains must be resisted. Therefore, maintaining temperatures to limit specified in code may not adequate prevent progressive failure. Without physical testing of the concrete liner to ascertain material properties and assess material condition, and, without performing computational fluid dynamic (CFD) modelling and numerical structural analysis that accounts for material property changes, it is difficult to quantify performance of the existing structural elements subjected to elevated temperatures to meet current NFPA 502 requirements. 6.5 Traffic Control As identified under Section 3.6.2 Existing Conditions, the critical traffic control needs to address are: · Install measures to close tunnel entrances to additional traffic while allowing access to emergency vehicles. · Install measures to stop upstream traffic prior to the fire site until it is safe to proceed as determined by the incident commander. · Provide means downstream of incident site to expedite flow of vehicles from the tunnel. · Define and implement system to allow incident commander to return operations to normal. · Install additional egress point within tunnel to meet 1,000 feet egress maximum spacing requirement. · Install emergency signage and markings to facilitate occupant egress. · Install upstream warning devices in advance of vehicle queues and alternate routes The following passages recommend measures to address the critical traffic control issues. 6.5.1 Close Tunnel Entrances to Additional Traffic To facilitate closure of the tunnel entrances to additional traffic while maintaining access to emergency vehicles, lane-use control signals should be installed at each portal entrance and at a location where it is desirable to stop vehicles along Route 15. Optionally, this secondary signal may be located at an upstream location which may allow for access to highway crossover. Due to the potential length of queues resulting from an incident inside the tunnel, the area controlled by the lane-use control signals may extend significantly. According to the MUTCD, lane use control signals shall be located such that road users will at all times be able to see one signal indication over a distance of up to 2,300 feet. A separate traffic study can model estimated queue lengths to determine a recommended design placement of multiple lane-use control signals, if necessary. Remote management from a traffic operations center would allow for the most responsive management of these lane-use control signals. 6.5.2 Control Upstream Traffic Prior to Fire Site Vehicles already downstream of the lane-use control signals at the time of the incident but still upstream of the fire site should be managed by both Dynamic Message Signs and auditory messages. Dynamic Message Signs should be installed at intervals within the tunnel to create partitioned sections. An operator can identify the sections of the tunnel which would require specific messages and activate the relevant DMS messages accordingly. Remote identification of the fire location relative to DMS locations would require a camera monitoring system, such as a Closed Caption Television (CCTV) system. In the event of a fire, thermal imaging camera systems may improve remote emergency identification as visibility of fire and tunnel occupants is not reduced by smoke or light glare. Remote management from a traffic operations center would allow for the most responsive management of the DMS and auditory messages. 6.5.3 Facilitate Traffic Flow Downstream of Fire Site Vehicles already downstream of incident may continue to exit the tunnel. Should it be determined by the incident commander that vehicular flow may continue adjacent to the incident, traffic control may be managed by both Dynamic Message Signs and Auditory Messages. Proper identification of the fire location relative to DMS locations would require a camera monitoring system, such as a Closed Caption Television (CCTV) system. An operator can identify the sections of the tunnel which would require specific messages and activate the relevant DMS messages accordingly. In the event of a fire, thermal imaging camera systems may improve remote emergency identification as visibility of fire and tunnel occupants is not reduced by smoke or light glare. Remote management from a traffic operations center would allow for the most responsive management of the DMS and auditory messages. 6.5.4 Return to Normal Operations An established incident commander must have an emergency protocol plan including fire and police emergency contacts along with a direct line of contact with the traffic operations center managing traffic control monitoring and response. Through coordination with these entities, the incident commander may determine the appropriate time to return operations to normal. 6.5.5 Additional Egress Location As noted previously, Heroes Tunnel does not meet the requirements for egress locations. The length of Heroes Tunnel is approximately 1,200 feet with no internal means of egress. NFPA 502 requires that exits for protection of tunnel occupants not exceed 1,000 feet spacing. An internal egress path must be installed between barrels for occupants to egress from one barrel to another barrel during an emergency evacuation. A door adjacent to the control room may be installed to provide egress between barrels.. However, it would not be safe for occupants to egress into the other tunnel barrel where traffic is moving at full speed. Under evacuation protocol, it will be necessary to stop traffic in both barrels to ensure occupancy safety. 6.5.7 Upstream Warning Devices As described previously, MUTCD (Manual on Uniform Traffic Control Devices) expressway guidance for Advance Warning Area Section 6C.04 recommends that upstream warning devices should be located a half mile or more in advance of the tunnel or the temporary traffic control zone. Upstream warning devices may also be placed in advance of alternate routes to better inform drivers. A system of permanent DMS installations at critical locations as part of an Incident Management System would provide the most responsive measure to control traffic along Route 15. DMS messages along Route 15 indicating a stopped condition and a description of the event within the tunnel will improve driver responsiveness to slowing and stopped conditions and allow opportunities to exit the highway and travel on local roads. By including regional installations at key interchanges such as Route 15 at the Milford Connector, I-95 at the Milford Connector, and I- 91 at Route 15, drivers may choose alternate regional routes to circumvent the temporary traffic control zone. 6.6 Electrical Systems This section serves as a summary of the electrical information presented in Section 3, 4, and 5. CDM Smith conducted an electrical review of the Heroes Tunnel through existing plans, past inspection reports, and a site visit. There are electrical code non-compliances and equipment is beyond its useful life. NFPA 502 lists several requirements for normal and emergency power systems within road tunnels. The existing power distribution system does not comply with NFPA 502, and the automatic transfer switch is potentially not functional. In addition, the conduit system at the tunnel shows signs of deterioration, including separation, cracking, and corrosion. Use of exposed PVC conduit within the tunnel is a life safety hazard and it should be replaced with metallic conduit. An entirely new electrical system is recommended; the replacement includes upgraded electrical utility services, new distribution equipment, conduit, and wiring. Additional redundancy is recommended through the use of two utility services (supplying two automatic transfer switches) during normal operating conditions and installation of an emergency generator which will operate during power outages. Emergency loads will be powered from an emergency motor control center that has main-tie-main configuration for operational flexibility. It is recommended that critical loads, including lighting, control, and communications equipment, be further backed up by an uninterruptible power supply. The lighting systems within the barrels are in poor condition and full replacement is recommended. Installation of ceiling centerline mounted LED lighting systems is recommended. During the day, light levels shall be high near the entry point of each tunnel to allow for eye adaptation and shall be incrementally reduced further into each tunnel. Nighttime luminance shall be constant throughout each barrel. It is recommended that a lighting control system be installed so that fixtures can be dimmed as required and scene setting can be programmed and operated both locally and remotely. During the day, it is recommended for the light output of the system to be controlled by a luminance photometer installed near the approach of each barrel. No egress or emergency lights exist at the tunnel. It is recommended that internally illuminated egress signs be located at each point of egress and throughout the tunnel. No gas or fire alarm systems exist in the tunnel. It is recommended for manual fire alarm pull boxes to be installed per code requirements. Spot-type heat detectors are recommended. Carbon monoxide probes and analyzers are recommended to be installed. It is recommended that all electrical distribution, control, and networking equipment be placed within a climate-controlled building. 6.7 Emergency Response Plan Going forward, coordinators and participating agencies will be required to have an emergency response plan. This includes the fire departments in Woodbridge, Hamden, and New Haven. As the elements and improvements recommended in this study are developed the planning can CDM Smith can provide the initial liaison service and the initial development of the emergency response plan.
A related document to the Heroes Tunnel Project Ventilation Study is the 293-page Technical Memorandum Appendix. These are the names of each Appendix, the page on which each section is found, and a brief overview of its contents.
· Appendix A, Existing Tunnel Plans, page 3-81, contains the original blueprints for the tunnel design, which are worth a look. · Appendix B, Reference Documents, NCHRP 216: National Cooperative Highway Research Project, pages 84-174, details a study that looked at how people act during emergencies in tunnels and how best to provide needed information to quickly get people to safety. The study recommendations are listed below the overview of each appendix. · Appendix C, Photographs, pages 175-193, contains photographs of various tunnel features. These are worth reviewing to see the current conditions. · Appendix D, Air Quality Technical Memorandum, pages 194-212, provides details about the current air quality conditions in the tunnel. Page 199 has a chart summarizing levels of various pollutants within the tunnel on the study date in January 2018. · Appendix E, Carbon Monoxide Technical Memorandum, pages 214-222, discusses carbon monoxide safety limits. The recommendation is that ventilation system maintain carbon monoxide levels at 50 parts per million or less. · Appendix F, Electrical Supporting Documents, pages 223-268, provides information on wiring and lighting systems. · Appendix G, Opinion of Probable Cost, pages 269-271, lists the estimated project costs. · Appendix H, FHWA Specifications for National Tunnel Inventory, pages 272-281, presents the U.S. Department of Transportation, Federal Highway Administration rating scale for rating the condition of road tunnels. · Appendix I, 2017 In-Depth Inspection for Tunnel No. 0073, pages 282-293, details a safety inspection of the West Rock Tunnel in 2017. The tunnel rated in poor condition with concrete that is cracked and peeling. There are no fire extinguishers or a fire detection system. The original four ventilation fans have been removed.
****** Appendix B, Reference Documents, NCHRP 216: National Cooperative Highway Research Project, Emergency Exit Signs and Marking Systems for Highway Tunnels, details a study that looked at how people act during emergencies in tunnels and how best to provide needed information to quickly get people to safety. The study is not summarized here, rather the recommendations are presented below. RECOMMENDATIONS (from the study) The study results highlighted the importance of communicating emergency information, including evacuation instructions when necessary, to vehicle drivers and occupants, and provided support for the use of the running man symbol on emergency exit signs. The study’s major recommendations are summarized below; these and additional recommendations are detailed further in the proposed guide. Emergency Evacuation Messages An emergency evacuation message should contain, at minimum, the following pieces of information: • A brief statement about the nature of the emergency, e.g., “fire in tunnel” or “vehicle fire ahead.” • Direct instructions about the action to take, e.g., “walk to exits” or “leave vehicles, walk to exits” if evacuation on foot is warranted. An evacuation direction should be specified (e.g., upstream of the fire) if applicable. • If slightly longer messages are possible, given the medium used, it may be beneficial to include a small amount of supplementary information. Useful supplementary information can include the identity of the person or agency making the announcement and additional instructions or guidance regarding exit locations and procedures. Emergency Exit Sign and Marking Formats The ISO (International Organization for Standardization) 7010 running man symbol (an exit sign with a stick figure person running) is recommended for use on emergency exit signs for highway tunnels. An additional recommendation is to include text specifying “EXIT” with the symbol, at least until the symbol achieves wider recognition in the United States. As specified in NFPA 502, signs indicating directions to emergency exits should be placed at least every 25 meters (82 feet) along the tunnel wall. These signs should include the running symbol and “EXIT” text, with the addition of a tailed directional arrow and the distance to the nearest exit in feet. If exits are located in two directions relative to the location of the sign, two signs should be placed side by side to indicate the directions and respective distances to the two exits. Exit path markings are recommended to supplement directional signs in guiding pedestrians to emergency exits. Markings should be placed no higher than 1 meter (3.3 feet) from the ground or trafficway surface. Exit doors should be marked with distinctive lighting as well as exit signs. The recommended lighting scheme is the one described by CIE 193-2010, including both illumination around the door and supplemental emergency strobe lights flashing at a rate of 1 to 2 Hz. Auditory beacons may be beneficial as a supplemental exit door marker, depending on acoustic conditions. Auditory beacons may be used to supplement (not replace) illuminated exit door lighting and, if used, should be calibrated to be audible to listeners who are in relatively close proximity to the exit door. The recommended sound is a simple, repeated voice announcement such as “exit here,” which may be in more than one language (in addition to English). Sign Technologies and Visibility Because of the severe degradation of sign contrast in smoke, the designed contrast ratio between sign backgrounds and legends should be as high as possible given the materials and colors used. This is one metric in which the tested PL signs scored higher than the tested LED illuminated signs. If internally illuminated signs are used, greater contrast can be achieved by maximizing the opacity of the negative/darker elements of the sign. Photoluminescent signs require ambient light in order to charge. If photoluminescent signs are used for emergency exits or path indicators, it is recommended that they be selected in consultation with a manufacturer that specializes in materials for tunnel environments, taking expected ambient light levels into consideration. Depending on the available power and control infrastructure, LED lights or photoluminescent markings may be used to delineate an emergency exit path for pedestrians. LED lights that can be controlled by tunnel operators to indicate a recommended direction to an exit (e.g., by illuminating in a sequence that indicates movement in a given direction) were considered particularly useful by most study participants, but any marker that is visible under a variety of potential emergency conditions (darkness, smoke, etc.) should be helpful to evacuees. |
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