GENERAL FIRE SAFETY REQUIREMENTS - GUIDELINES ANNEX


GA 7.0 VENTILATION AND SMOKE CONTROL
GA_7.0 – Revisions_2015
Item No. Provisions Notes
1 Scope and Purpose  
  This fire safety standard applies to natural and mechanical methods of smoke control where required by other fire safety standards of the Qatar Civil Defence Department. The purpose of this standard is to establish the minimum requirements in the design of smoke control system that are required to provide a tenable environment for escape, evacuation or relocation of occupants and compliment firefighting operations.  
2 General Design Requirements  
  Buildings or structures or parts thereof that are required to have smoke control system shall be designed according to the latest edition of applicable NFPA codes/standard and this general fire safety requirements guidelines annex GA_03. The requirements of this guidelines annex shall be upheld in case of conflict with NFPA 92.  
3 Applications  
 

Smoke Control Systems are classified into two general categories as smoke containment and smoke management.

  • Smoke Containment – smoke control method that employs mechanical equipment to produce pressure difference across smoke barriers
  • Smoke management – A smoke control method that utilizes natural or mechanical systems to maintain a tenable environment in the means of egress from a large volume space or to control and reduce the migration of smoke between the fire area and communicating spaces
 
4 Methods of Smoke Control  
4.1 Pressurization Method  
 

Controlling smoke by pressure differences across smoke barriers though the aid of mechanical means is one of the acceptable procedures in smoke control. This procedure does not require the maintenance of a tenable environment in the zone of fire origin.

Design of pressurization system shall be in accordance with NFPA 92 and this standard.

 
4.2 Airflow Method  
 

Design and application shall be in accordance with NFPA 92.

Engineering analysis which shall be performed to establish that usage of this procedure will not cause adverse effect to other portions of the smoke control system, further intensify the fire, disrupt flume dynamics and interfere with exiting.

 
4.3 Exhaust Method  
  Smoke control systems employing the exhaust method shall be designed in accordance with NFPA 92 and this standard. The minimum height to which the smoke layer interface shall be designed shall be 1.83 m (6 ft) above any walking surface that forms part of the required egress system within the smoke zone.  
4.4 Smoke Containment (Pressurization) Systems  
4.4.1 Zoned Control System  
4.4.1-1 The minimum pressure difference across a smoke barrier shall be 12.5 Pa (0.05 in.w.g.) in fully sprinklered building  
4.4.1-2 In non-sprinklered and other than fully sprinklered buildings , the minimum pressure difference shall be equivalent to two times the calculated maximum pressure difference that can be produced by the fire  
4.4.1-3 The maximum pressure difference across a smoke barrier shall be determined by required door opening forces which shall not exceed 110 N.  
4.5 Smoke-proof Enclosure (Exit Staircases)  
4.5.1 Mechanical Pressurization Alternative  
4.5.1-1 Stairwell pressurization system shall be designed so that a minimum 12.5 Pa pressure difference between the stairwell and the occupant area or smoke zone is maintained for buildings that are fully sprinklered.  
4.5.1-2 Stairwell pressurization system shall be designed so that a minimum 25 Pa pressure difference between the stairwell and the occupant area or smoke zone is maintained for buildings that are non-sprinklered or other than fully sprinklered.  
4.5.1-3 Pressurization air supply shall account allowance for open doors. A minimum 1 m/s airflow velocity shall be maintained across open doors with the pressure difference across the other closed doors and the smoke zone not be lower than 12.5 Pa.  
4.5.1-4 Minimum allowance of two (2) doors open shall be permitted for residential apartments and business occupancies that are not classified as high rise.  
4.5.1-5 Minimum allowance for three (3) doors open shall be accounted to all exit stairwells in occupancies which are of public resort and are required to be pressurized. Where the stairwell connects three storeys, allowance for two (doors) open, the doors in fire floor and the final exit discharge, shall be permitted. Where the number of stories does not have the equivalency or less than the number of doors required for the stairwell to be opened; in this case the design shall consider the velocity criterion having either the door in the fire floor or final exit discharge open.  
4.5.1-6 Minimum allowance of three (3) doors open shall be accounted to all exit stairwells in high rise buildings  
4.5.1-7 The maximum pressure differential between the stairwell and the fire zone shall be determined by the required door opening force which shall not exceed 110 N.  
4.5.1-8 Pressurization air shall be supplied such that uniform pressure inside the stairwell is attained.  
4.5.1-9 Single injection system shall be permitted where the exit stairwell connects not more than five (5) floor levels or height of not more than 18 m to include basements.  
4.5.1-10 Single injection system shall be permitted for exit stairwells connecting more than five (5) floor levels or height of 18 m where engineering analysis confirms its applicability.  
4.5.1-11 Pressurization air injection points in a multiple injection system shall be distributed not more than three (3) floor levels apart, but in no case shall exceed 11 m.  
4.5.1-12

Pressurization air supply intake shall be located away from building exhausts which can cause smoke from the building being injected to the exit stairwell.

A minimum separation distance of five (5) meters, measured horizontally, shall be maintained between air intakes and exhausts.

Pressurization air supply intakes shall be oriented vertically by at least 1 m below building exhausts.

 
4.5.1-13 Means of controlling the required pressure inside the stairwell shall be provided.  
4.5.2 Natural Ventilation Alternative  
4.5.2-1 Exit staircases accessed through open and externally located vestibules are deemed to satisfy natural ventilation alternative.  
4.5.2-2

Exit staircases accessed through vestibule having a minimum net area of 1.5 sq. m (16 sq. ft.) opening in a wall facing an outer yard, court or public way that is at least 6.1 m (20 ft) wide are deemed to satisfy natural ventilation alternative.

Side hung windows opening outward a minimum of 30° capable of being opened automatically through remote control switch linked to the building fire alarm system is an acceptable arrangement.

 
  Exit staircase with fixed or automatic ventilation opening of not less than 50% of the total wall area at each floor/storey level in exit staircases located along perimeter walls of the building facing the outer courtyard or public way that is at least 6.1 m (20 ft) wide  
  Exit staircase with fixed or automatic ventilation opening of not less than 50% of the total wall area at each floor/storey level facing an air/light well that is open to the sky having a minimum clear width of 10 meters *** Note: Permitted for staircases in non-high-rise building that does not connect below ground or basement levels
  Exit staircases with fixed or automatic opening having a minimum net area of 1.5 square meter at the top of the stairwell shaft ***Note: Permitted for staircases in medium rise buildings that connects one floor level below ground or basement only.
4.6 Smoke-stop and Fire Fighting Lobbies  
4.6.1 Mechanical Pressurization Alternative  
4.6.1-1 Fresh air supply at the rate equivalent to 10 ACH or that is capable of maintaining 12.5 Pa (0.05 in. w.g.) pressure difference between the smoke-stop or firefighting lobby and the smoke zone shall be designed for the smoke-stop or lobby pressurization system.  
4.6.1-2 The pressure in the lobby shall in no case be higher than the pressure in the stairwell.  
4.6.1-3 Means of controlling the required pressure in the lobby shall be provided.  
  following input parameters shall be considered in the design.  
4.6.2 Natural Ventilation Alternative  
4.6.2-1 Open and externally located lobbies are deemed naturally ventilated lobbies satisfying natural ventilation alternative.  
4.6.2-2

Lobbies having openings on external wall meeting all of the following conditions are deemed naturally ventilated lobbies satisfying natural ventilation alternative:

a. a minimum net area of 1.5 sq. m (16 sq. ft.) or 25% of the floor area of the lobby, whichever is greater
b. openings are located as near as practicable to the ceiling with the top of the opening at least 0.3 m (1 ft) below the ceiling of the lobby
c. openings are facing an outer court, yard or public way that is at least 6.1 m (20 ft) width; or

c.1 when facing an air/light well, the well should be totally open to the sky and have an area of not less than 10 m² with no sides less than 3 m

Note (c.1) : Permitted in non-high rise building having no floor levels below ground. Air/light well starts from ground level only.

Note (c.1) : Permitted in non-high rise building having no floor levels below ground. Air/light well starts from ground level only.
  Lobbies located one floor level or 3.5 m below ground, may be ventilated through unobstructed openings having a minimum cross-sectional area of 1 m² provided at the ceiling of the lobby and discharging directly to external of the building. Duct and/or shafts required to ventilate the lobby to external shall be constructed of materials having minimum 1 hr fire protection rating or equivalent rating of the lobby enclosure, whichever or greater.  
4.6.2-3 Smoke-stop or firefighting lobbies approached via cross ventilated corridors having fixed ventilation openings of not less than 50% of the corridor walls located in at least two of its externally opposing walls and with no part on the floor space of the corridor is farther than 12 m from the ventilation openings are deemed to satisfy natural ventilation alternative.  
4.7 Car Parks  
4.7.1 Mechanical Ventilation/Smoke Control  
4.7.1-1 Car park mechanical ventilation and smoke control systems employing duct works shall be designed in accordance with NFPA 88A and ASHRAE Handbook.  
4.7.1-2 Ventilation exhausts providing minimum 10 ACH shall deemed to satisfy smoke control requirements. Duct works shall be designed with high level and low level exhaust inlets. Low level exhaust inlets shall constitute at least 50% of the required smoke extraction area.  
4.7.1-3 Car park ventilation systems employing thrust fans shall be confirmed through performance based analysis. The use of CFD fire modeling and the following input parameters shall be considered in the design.  
4.7.1-4

Minimum design fire size for enclosed parking structures that permits only passenger cars shall be according to anticipated fuel load of one car but in no case be less than

a) 4 MW (2 m x 5 m) for car parks protected by supervised automatic sprinkler system
b) 8 MW (5 m x 5 m) for car parks not protected with supervised automatic sprinkler system
 
4.7.1-5 Minimum design fire size for enclosed car parking structures that permits goods carrying vehicles shall consider the combined fuel load of the car and the goods.  
4.7.1-6 Assumed design fire for a car shall be flaming polyurethane.  
4.7.1-7 The design fire must be considered to be in the most onerous location, preferably the most remote location from the exhaust points and at a point in-between two zones for zoned systems.  
4.7.1-8

The following acceptance criteria at 1.8 m above the floor level shall be attained within a 10 m radius location of the design fire during the first twenty (20) minutes of the fire

a) Minimum 10 m visibility upstream of the fire
b) Temperature of the smoke layer does not exceed 60°C
 
4.7.1-9

Duration of CFD simulation must be a minimum of 30 minutes.

Grid size must be a maximum of 0.2 m x 0.2 m x 0.2 m within 10 m of the design fire and maximum 0.4.m x 0.4 m x 0.4 m for other areas.

 
4.7.1-10 Design shall include a margin of safety considering possible loss of thrust fans. The analysis shall include a sensitivity study that shows that even with the loss of a thrust fan nearest the fire, the acceptance criteria are still met.  
4.7.1-11 Exhaust fans must be configured such that failure of any single fan will not result in more than 50% reduction of air flow.  
4.7.1-12 Exhaust fans shall have alternate source of power in accordance with Section 10 hereof.  
4.7.1-13 Where multiple levels of enclosed car parks are protected by the same ventilation system, the size of the equipment as well as the inlets and outlets for the make-up and exhaust air must be adequately designed to allow for simultaneous CO dilution of adjacent zones and other levels at the minimum rate of 6 ACH.  
4.7.2 Natural Ventilation  
4.7.2-1 Car parks with openings that is 40% of its total enclosure area in at least two of its opposing walls is deemed satisfying natural ventilation alternative  
4.7.3 Use of Smoke Vents  
4.7.3-1 Provisions of smoke vents shall be permitted in enclosed car parks of residential apartments and business occupancies whose aggregate floor area does not exceed 1000 sq. m.  
4.7.3-2 Provisions of smoke vents shall be permitted for car parks of residential apartments and business occupancies 1000 sq m or less that is located not more than two (2) levels and 6 m below ground level.  
4.7.3-3 Number and sizes of vents shall be such that aggregate vent opening is equivalent to not less than 2.5% of the floor being served. No smoke vent shall be smaller than 0.6 m diameter or width.  
4.7.3-4 Vents shall be distributed along the perimeter, on the sides or ceiling level of the car park with the vents spaced no farther than 30 m from each other.  
4.7.3-5 Separate vent outlets shall be provided for each floor level.  
4.7.3-6 Where ducts are required to connect the vents to its outlets outside, the duct shall be constructed to provide 1 hour fire resistance.  
4.7.3-7 Smoke vents which are kept closed during normal or non-fire condition shall be designed to operate automatically.  
4.7.3-8 In car parks provided with automatic sprinklers, the provision of smoke vents shall be designed such that it does not affect the sprinkler activation.  
4.8 Atrium and other Large Spaces  
4.8.1 Smoke control system designed in accordance with NFPA 90 shall be provided for atriums or similar communicating spaces in buildings that connects more than 3-storeys.  
4.8.2 Smoke control system designed in accordance with NFPA 92 shall be provided to any compartment or part in a building which has a total floor area of more than 5000 sq. m  
5 Fire Command Center  
5.1

Fire command center for fire department operations shall be provided and comply with the following requirements:

- Located along external wall of the building with safe and direct access from external, or as recommended and approved by QCDD
- Separated from the remainder of the building by not less than 2-hrs enclosure
- Room shall have a free working space of at least 9m2 minimum area (any side least dimension of 2.5m) with at least 1m unobstructed clearance from all equipment.
- Contain the smoke control panels and other control equipment relative to the building’s fire alarm
- Can serve the function of fire fighter’s smoke control station
- With provisions for ventilation and smoke control
- Comply with NFPA 72 requirements
 
6 Smoke Control Panel  
6.1

The fire fighter’s control panel shall provide control capability over the equipment of the smoke control system in the building by:

a. ON-AUTO-OFF control over individual equipment of the smoke control system that can also be controlled from other sources in the building
b. OPEN-AUTO-CLOSE control over individual dampers relating to smoke control system that can also be controlled from other sources in the building
c. ON-OFF or OPEN-CLOSE or START-STOP control over smoke control system and other critical equipment associated with fire or smoke emergency and that can only be controlled from the fire fighter’s control panel

Manual activation/de-activation Switch

Override Switch

6.2 Switch for manual control of the system shall be of rotary selector type Use of push button type switch is discouraged
7 Equipment  
7.1 Equipment such as, but not limited to, fans, ducts, fire dampers, smoke dampers and combination fire-smoke dampers shall be suitable for its intended use and approved by QCDD.  
8 Detection and Control Systems  
8.1 Fire detection systems required to provided control signals to mechanical smoke control systems or elements thereof shall comply with NFPA 72. Such detection systems together with its control unit shall be listed for smoke control applications.  
9 Smoke Control System Activation  
 

Activation of smoke control systems must be automatic using either of the following initiating methods:

a) Sprinkler flow switch
b) Smoke detection system
c) Heat detection system

Analysis on the possible effect of the smoke control (ventilation) system on the sprinkler system response shall be considered in the design.

 
10 Power Supply Systems  
10.1

Smoke control systems shall be supplied with two (2) power sources. Primary power shall be from the normal building power supply system but shall have separate or independent connection from the building non-fire safety related installations.

Secondary power supply shall be from an approved standby power supply system complying to NFPA 101.

 
10.2 Transfer from the normal to full standby power shall be automatic and within 60 seconds of failure of the primary power supply.  
10.3 Wiring for operation and control of smoke control systems shall be connected ahead of the main disconnect and protected against possible exposure to fire.  
10.4 Mechanical smoke control systems that are designed as a combined system or which are used to serve multiple control zones (e.g. stairwell and its

associated smoke-stop lobby) shall have both a backed up power supply and equipment, such as standby fan.

One additional fan is required as standby fan for each system feed by a single fan.

Where a particular control zone is being protected by a mechanical smoke control system having two or more fans of equal capacity, the system could be backed up by an additional fan having the same capacity of the other fans.

Where a particular control zone is being protected by a mechanical smoke control system having more than one fan of different capacities, the system could be backed up by an additional fan having the same capacity of the largest fan.

 
11 Commissioning and Acceptance Testing  
  The commissioning and acceptance testing of smoke control systems must be carried out in the presence of a QCDD inspector. The procedure must consists a hot smoke test prepared and carried out in accordance with AS 4391. For jet fans, BS 7346, Part 7 may be used as a guide.