CERTIFICATION, DESIGN, CONSTRUCTION, OPERATION AND MAINTENANCE
GUIDELINES for BRITISH COLUMBIA COMMUTER RAILWAYS
Part 5 Appendix VIII
Design and Performance Standards for Emergency Ventilation Systems
Section #
Requirement
Source/Rationale
5.8.1
Emergency Ventilation – General
(a) The following guidelines apply to the design and performance standards for
the environmental conditions and the mechanical and non-mechanical
ventilation systems used to meet those safety requirements for a fire
emergency in a system station or guideway.
(b) The requirement for a mechanical or non-mechanical system intended for
the purpose of emergency ventilation shall be determined in accordance
with subsections 5.8.1 (c) through subsections 5.8.1 (f) requirements.
(c) For length determination all continuous enclosed guideways and
underground system stations segments between portals shall be included.
(d) A mechanical emergency ventilation system shall be provided in the
following locations:
(i)
in an enclosed system station, and
(ii) in a system underground or enclosed guideway that is greater in length
than 300 m (984 ft).
(e) A mechanical emergency ventilation system shall not be required in the
following locations:
(i)
in an open system station, and
(ii) where the length of an underground guideway is less than or equal to
60 m (197 ft).
(f) Where supported by an engineering analysis a non-mechanical emergency
ventilation system shall be permitted to be provided in lieu of a mechanical
emergency ventilation system in the following locations:
(i)
where the length of the underground or enclosed guideway is less than
or equal to 300 m (984 ft) and greater than 60 m (187 ft), and
Adapted from NFPA 130 section 7.1.1 through
7.1.4
1
5.8.1
continued
in an enclosed station where engineering analysis indicates that a
non-mechanical emergency ventilation system supports the tenability
criteria of the project.
(g) In the event that an engineering analysis is not conducted or does not
support the use of non-mechanical emergency ventilation system for the
configurations described in subsection 5.8.1 (f) a mechanical emergency
ventilation system shall be provided.
(h) The engineering analysis of the ventilation system shall include a validated
subway analytical simulation program augmented as appropriated be a
quantitative analysis of air flow dynamics produced in the fire scenario, such
as would result from the application of validated computational fluid
dynamics (CFD) techniques.
(i) The results of the analysis in subsection 5.8.1 (h) shall include the no-fire (or
cold) air velocities that can be measured during commissioning to confirm
that a mechanical ventilation system as built meets the requirements as
determined by the analysis.
(j) Where required by section 5.8.1 the mechanical emergency ventilation
system shall make provisions for the protection of passengers, employees
and emergency personnel from fire and smoke during a fire emergency and
shall be designed to maintain the required air flow rates for a minimum of 1
hour but not less than the anticipated evacuation time.
5.8.2
Design
(a) The emergency ventilation shall be designed to do the following:
(i)
provide a tenable environment along the path of egress form a fire
incident in enclosed stations and enclosed guideways;
(ii)
produce airflow rates sufficient to prevent backlayering of smoke in the
path of egress within enclosed guideways;
(iii) be capable of reaching full operational mode within 180 seconds, and
(iv) accommodate the maximum number of trains that could be between
ventilation shafts during an emergency.
(b) The design shall encompass the following:
(i)
the heat release rate produced by the combustible load of a vehicle
and any other combustible materials that could contribute to the fire
load at the incident site;
(ii)
the fire growth rate;
(ii)
2
Adapted from NFPA 130 section 7.2.1 through
7.2.4
5.8.2
continued
station and guideway geometries;
a systems of fans drafts and devices for directing air flow in stations
and guideways;
(v) a program for determining emergency response procedures capable
of initiating prompt response from the central supervising station in the
event of a fire emergency, and
(vi)
a ventilation system reliability analysis that as a minimum considers
electrical subsystems, mechanical reliability and supervisory controls.
(c) The system reliability analysis in paragraph 5.8.2 (b) (vi) shall consider as a
minimum the following events:
(i)
fire in a guideway or station;
(ii) local incident within the electrical utility that interrupts power to the
emergency ventilation system, and
(iii) derailment.
(d) The design and operation of the signaling or train control system, traction
power blocks and ventilation system shall be co-coordinated to match the
total number of trains that could be between ventilation shafts during an
emergency.
5.8.3
Emergency Ventilation Fans
(a) The ventilation system fans that are designated for use in fire emergencies
shall be capable of satisfying the emergency ventilation requirements to
move tunnel air in either direction as required to provide the needed
ventilation response.
(b) Individual emergency ventilation fan motors shall be designated to achieve
their full operating speed in no more than 30 seconds from a stopped
position when started across the line and no more than 60 seconds for
variable speed motors.
(c) The ventilation system designated for use in emergencies shall be capable
of operating at full capacity in either the supply of or exhaust mode to
provide the needed ventilation response where dilution of noxious products
is to be minimized.
(d) Emergency ventilation fans, their motors and all related components expose
to exhaust air flow shall be designed to operate in an ambient atmosphere
of 2500C (4820F) for a minimum of 1 hour.
(iii)
(iv)
3
Adapted from NFPA 130 section 7.3.1 through
7.3.6.1
5.8.3
continued
(e) A design analysis shall be permitted to be used to reduce this temperature,
however, it shall not be less than 1500C (3020F)
(f) Fans shall be rated in accordance with ANSI/AMCA 210, AMCA 250, AMCA
300, ASHRAE Handbook – Fundamentals and SSHRAE 149 requirements.
(g) Local fan motor starters and related operating control devices shall be
located away from the direct airstream of the fans to the greatest extent
possible.
(h) Thermal overload protection devises on motor controls used for emergency
ventilation shall not be permitted.
(i) Fans that are associated only with passenger or employee comfort and that
are not designed to function as a part of the emergency ventilation system
shall shut down automatically on identification and initiation or a fire
emergency ventilation program so as not to jeopardize or conflict with
emergency airflows.
(j) Non-emergency airflows that do not impact the emergency airflows shall be
permitted to be left operational where identified in the engineering analysis.
(k) Critical fans required in battery rooms or similar spaces where hydrogen
gases or other hazardous gases may be released shall be designed to meet
the requirements of NFOPA 91.
(l) These fans and other critical fans in automatic train control rooms and so
forth shall be identified in the engineering analysis and shall remain
operational as required during the fire emergency.
5.8.4
Devices
(a) Devices that are interrelated with the emergency ventilation system and that
area required to meet the emergency ventilation airflows shall be structurally
capable of withstanding both maximum repetitive and additional piston
pressures of moving trains and emergency air flow pressures.
(b) Devices that are subject to exposure to the fire anticipated in the design of
the emergency ventilation system and that are critical to the effective
functioning in the event of the emergency shall be constructed of noncombustible, fire resistive materials and shall be design to operate in an
ambient atmosphere of 2500C (4820F) for a minimum of 1 hour.
(c) A design analysis shall be permitted to be used to reduce this temperature,
however, it shall not be less than 1500C (3020F)
4
Adapted from NFPA 130 section 7.4
5.8.4
continued
(d) Finishes applied to non-combustible devices are not required to meet the
requirements of subsection 5.8.4 b).
(e) Devices shall be designed to operate throughout the maximum anticipated
temperature range.
5.8.5
Shafts
(a) Shafts that penetrate the surface and that are used for intake and discharge
in fire or smoke emergencies shall be positioned to prevent recirculation of
smoke into the system through openings.
(b) In the configuration require by subsection 5.8.5 (a) is not possible, surface
opening shall be protected by other means to prevent smoke from reentering the system.
(c) Adjacent structures and property uses shall also be considered.
Adapted from NFPA 130 section 7.5
5.8.6
Emergency Ventilation System Control/Operation
(a) Operation of the emergency ventilation system components shall be initiated
from the central supervising station.
(b) The central supervising station shall receive verification of proper response
by emergency ventilation fan(s) and interrelated device(s).
(c) Local controls shall be permitted to override the central supervising station in
all modes in the event the central supervising station becomes inoperative
or where the operation of the emergency ventilation system components is
specifically redirected to another site.
(d) Operation of the emergency ventilation system shall not be discontinued
until directed by the incident commander.
Adapted from NFPA 130 section 7.6
5.8.7
Power and Wiring
(a) The design of the power for the emergency ventilation system shall conform
to the requirements of Article &00 of NFPA 70,
(b) Alternatively the design of the power for the emergency ventilation system
shall be permitted to be based upon the results of the electrical reliability
analysis as per paragraph 5.8.2 (b) (vi) as approved by the authority having
jurisdiction.
Adapted from NFPA 130 section 7.7
5
5.8.7
continued
(c) All wiring materials and installations shall conform to the requirements of
NFPA 70 and in addition, shall satisfy the requirements of subsections 5.8.7
(d) through 5.8.7 (p).
(d) Materials manufactured for use as conduits, raceways, dusts, boxes,
cabinets, equipment enclosures and their surface finish materials shall
withstand temperatures up to 5000C (9320F) for 1 hour and shall not support
combustion under the same temperature conditions.
(e) Other materials, referred to in subsection 5.8.7 (d), if encased in concrete
shall be acceptable.
(f) All conductors shall be insulated.
(g) Ground wire installed in metallic raceways shall be insulated.
(h) Other ground wires shall be permitted to be bare.
(i) All thickness of jackets shall conform to NFPA 70 requirements.
(j) All insulations shall conform to Article 310 of NFPA 70 and shall be moisture
and heat resistant types carrying temperatures ratings corresponding to
either of the following conditions:
(i)
750C (1670F) for listed fire resistive cables, and
(ii) 900C (1940F) for all other applications.
(k) Wire and cable construction intended for use in control circuits and power
circuits to related emergency devices shall be listed as being resistant to the
spread of fire and shall have reduced smoke emissions.
(l) Cables shall be permitted to be listed by any of the following methods:
(i)
the cable does not spread fire to the top of the tray in the vertical-tray
flame test in section 1160 of UL 1581 and the cable exhibits s specific
optical density of smoke at 4 minutes into the test that does not
exceed 200 in the flame test mode and 75 in the non-flaming mode
when tested in accordance with ASTN E 662;
(ii)
the cable exhibits damage (char length) that does not exceed 1,500 m
(4.9 ft) when the vertical flame-test with cables in the cable trays is
performed as described in CSA C22.2 No. 0.3 and the cable exhibits a
specific optical density of smoke at 4 minutes into the test that does
not exceed 200 in the flaming mode and 75 in the non-flaming mode
when tested in accordance with ASTM E 662;
(iii) the cable is listed as a limited smoke cable (/LS) by meeting the
damage height, total smoke released and peak smoke release rate
criteria required when tested in the vertical tray flame test in UL 1685;
6
5.8.7
continued
(iv)
when testing in the UL vertical tray flame exposure the cable damage
shall be les than 2,200 mm (8.2 ft) when measured from the bottom of
the cable tray;
(v) when testing in the UL vertical tray flame exposure the total smoke
release rate shall not exceed 95 m 2 (1,023.6ft2) when measured from
the bottom of the cable tray;
(vi) when testing in the UL vertical tray flame exposure the peak smoke
release rate shall not exceed 0.26 m 2 (2.7 ft2);
(vii) alternatively when the cable is tested in the EEEI 1202 flame
exposure the cable damage height shall not be less than 1,500 mm
(4.9 ft) when measured from the lower edge of the burner face;
(vii) and when the cable is tested in the EEEI 1202 flame exposure the
total smoke releases shall not exceed 150m 2 (1,615 ft2);
(viii) and when the cable is tested in the EEEI 1202 flame exposure the
peak smoke release rate shall not exceed 0.40 m 2/s (4.3 ft2/s);
(ix)
the cable is listed as having fire-resistant characteristics capable of
preventing the carrying of fire from floor to floor by being capable of
passing the requirements of the ANSI/UL 1666 and the cable exhibits
a specific optical density of smoke at 4 minutes into the tests that
does not exceed 2000 in the flaming mode and 75 in the non-flaming
mode when tested in accordance with ASTN E 662, and
(x)
the cable is listed as having adequate fire-resistant and low smoke
producing characteristics by having a flame travel distance that does
not exceed 1,500 m (4.9 ft), generating a maximum peak optical
density of smoke of 0.5 and a maximum average optical density of
smoke of 0.15 when tested in accordance with NFPA 262.
(m) All conductors for emergency ventilation fans and related emergency
devices routed through the stations and/or guideway shall be protected from
physical damage from rolling stock or other normal operations and from fires
in the system by one of the following:
(i)
suitable embedment or encasement;
(ii) routing of such conductors external to the interior underground portions
of the transit system facilities;
(iii) diversity in systems routing (such as separate of redundant or multiple
circuits, circuits or with a physical diverse network topology) so that a
single fire or emergency event in the station will not lead to a failure of
the system, or
7
5.8.7
continued
(iv)
(n)
(o)
(p)
(q)
(r)
use of fire-resistive cable systems with a minimum 1 hour rating in
accordance with subsection 5.8.7 (r).
Except in ancillary areas or other non-public areas encased conductors shall
be enclosed in their entirety in armor sheaths, conduits or enclosed raceway
boxes and cabinets.
Conductors in conduits or raceways shall be permitted to be embedded in
concrete electrical duct banks.
Over-current elements that are designed to protect conductors serving
motors for both emergency fans and related emergency devices that are
located in spaces other than the main electrical distribution system
equipment rooms shall not depend on thermal properties for operation.
For electrical substations and distribution rooms serving emergency
ventilation systems where the local environmental conditions require the use
of mechanical ventilation or cooling to maintain the space temperature
below the electrical equipment operating limits, such mechanical ventilation
or cooling systems shall be designed that the failure of any single air moving
unit does not result in the loss of the electrical supply to the tunnel
ventilation fans during the specified period of operation.
Where fire resistive cables are permitted they shall be listed and have a 1
hour fire resistive rating in accordance with UL 2169 and shall be installed
per the listing requirements.
8