MECHANICAL VENTILATION SYSTEM for BUSINESS OCCUPANCY

MECHANICAL VENTILATION SYSTEM for BUSINESS OCCUPANCY
Occupancy Classification	Building Configuration	Ventilation & Smoke Control Requirements
Ventilation System in Smoke Proof Enclosure	Mechanical Ventilation, Extract / Smoke Ventilation Exhaust System
Max. Area (sq.m.)	Habitable Height (m)	Exit Staircase	Smoke-Stop Lobby	Fire Fighting Lobby	Basement	Fire Pump Room	Generator Room	Fire Command Center	Atrium, Communicating Space	Zoned Smoke Controlled Spaces
LOW RISE BUILDINGS	≤500	≤15	R¹ ***	R ² ***	R ² ***	R ⁴	R ⁶ ***	R ⁷ ***	R ⁸ ***	R ⁵	R ³
MEDIUM RISE BUILDINGS TYPE A	>50 to ≤1,000	>15 TO ≤18	R¹	R ²	R ²	R ⁴	R ⁶	R ⁷	R ⁸	R ⁵	R ³
MEDIUM RISE BUILDINGS TYPE B	>1,000	>18 TO ≤28	R¹	R ²	R ²	R ⁴	R ⁶	R ⁷	R ⁸	R ⁵	R ³
HIGH RISE BUILDINGS	UL - UNLIMITED AREA	>28	R¹	R ²	R ²	R ⁴	R ⁶	R ⁷	R ⁸	R ⁵	R ³

Note:
* Other requirement not covered nor specified in this standard / guideline must be referred to relevant NFPA code & standards or consult with QCDD engineers for compliance.
** For superscript descriptions, refer to Addendum.
*** Provide Ventilation if the Smoke/Fire Enclosure or MEP Rooms were provided.
**** Smoke control system shall be supplied with 2 power sources.
Provides control capability over equipment of the smoke control system.

Superscript Description:

1 - Staircase Area

a. Mechanical Pressurization Method

Stairwell / Shaft:
a.1 Minimum Design pressure difference (_P) across smoke barrier: AS=0.05 inch.w.g. (12.5 Pascal), NS=0.1 inch.w.g. (25 Pascal)
a.2 Minimum 1 m/s airflow velocity across open doors and _P of not lower than 12.5 Pa (0.05 inch.w.g.) across other closed doors and smoke zone:

* Required minimum three (3) doors-open for High-Rise Building
* Required minimum three (2) doors-open for Non-High-Rise Building

a.3 Single Injection Stairwell Pressurization System: Permitted for stairwell traverses up to five (5) floor levels or 30.5 meters (100 feet) in height, whichever is the least, otherwise provide multiple injection system with injection points distributed no farther than an interval of three (3) floor levels.
a.4 Pressurization air supply intakes located preferably 5 meters (16.4 feet) away from building exhausts; minimum 1 meter (3.28 feet) below building exhaust where oriented vertically.
a.5 Maximum the door opening force which shall not exceed 110 newton (24.73 lbf).
a.6 Acceptable means for controlling the pressure for Staircase Pressurization Fan.

b. Natural Ventilation Method: (Note: For No Basement, ≤5 Floor Level)

Stairwell / Shaft:
b.1 For building staircases traversing 5-storeys with maximum two (2) basements of not more than 6 meters below grade level and with less than 18 meters of habitable height:

Acceptable configurations: 2B+G+2, B+G+3, G+4 or less
b.1.1. Exit staircases with fixed or automatic opening having a minimum clear area of 1.5 sq.m. at the top of the stairwell shaft or;
b.1.2. In accordance with item b.2.1 to b.2.3

b.2 For building staircases traversing 6 storeys with maximum two (2) basements of not more than 6 meters below grade level and with less than 18 meter habitable height:

Acceptable configurations: 2B+G+3, B+G+4, G+5 or less
b.2.1. Exit staircases accessed via vestibule/lobby having a minimum net area of 1.5 square meters (sqm) opening in a wall facing an outer couurt yard or public way that is at least 6.1 meters wide. Single basement not more than 3 meters below grade level may be permitted without the opening.
b.2.2 Exit staircases with fixed or automatic ventilation opening of not less than 50% of the total wall area at each floor / story level in exit staircases located along perimeter walls of the building facing the outer courtyard or public way hat is at least 6.1 meters wide. Single basement not more than 3 meters belwo grade amy be permitted without opening.
b.2.3 Exit staircases with fixed or automatic ventilation opening of not less than 50% of the total wall area at each floor / story level next to an air/light well that is open to the sky having minimum area of 10 sq.m. with no side less than 3 meters. Single basement not more than 3 meters below grade level may be permitted without the opening.

b.3 For High-rise buildings and/or buildings having three (3) or more basments:

b.3.1. Mechanical Pressurization method as stipulated in item 1.1 shall be highly recommended in all internal and external staircases for this type of buildings.
b.3.2. Natural ventilation shall only be allowed in external exit staircases that can provide a minimum of 50% opening on the side of its superficial wall in every floor level
b.3.3. A combination of mechanical pressurization and natural ventilation method stipulated in a & b may be permitted in a case to case basis.

2. Smokestop Lobby and Fire-fighting Lift Lobby:

a. Mechanical Ventilation Alternative

a.1 Positive ventilation (supply mode only) at the rate of 10 ACH

b. Natural Ventilation Alternative (Note: for the Lobbies were at external side of the building)

b.1 Lobbies having openings on external wall meeting the following conditions:
b.1.1 Minimum net area of 1.5 square meters (sqm) or 25% of the floor area of the lobby, whichever is greater
b.1.2 Openings are located as near as practicable to the ceiling and the top of the opening is not more than 300 millimeters from the ceiling line.
b.1.3 Openings are facing an outer courtyard or public way that is at least 6.1 meters wide when facing an air/light well, the well is totally open to the sky and have an area of not less than 1 square meter per meter (sqm/m) height of enclosing well.

*Note. Permitted in non-high rise building (<5 floor level), and the air/light well starts from ground level only,

b.2 Lobbies below ground level may be ventilated through unobstructed openings having a minimum net cross section of 15% of the floor area of the lobby provided at the ceiling of the lobby and discharging directly to the external of the building.

*Note. Permitted up to 3 floor levels or 9 meters (m) below ground level, whichever is the least and exit staircase being served not connecting upper floor levels and is open to external

3. Smoke Controlled Zones (spaces protected under zoned smoke control principles)

a. Minimum Design pressure dirfference (AP) across smoke barrier: AS=0.05 inch. w.g. (12.5 Pascal)
b. In non-sprinklered and other than fully sprinklered building, pressure difference equivalent to two (2) times the calculated maximum pressure difference that can be produced by the fire
c. Maximum pressure difference across a smoke barrier shall be determined by the required door opening force which shall not exceed 110 newtons (N).

4. Basements/Car parks Ventilation:

(Note: The following conditions does not apply for Open-Parking Structure, R (>2B) - Required where there are two (2) or more basements)
a. Mechanical Ventilation Alternative (Arrangement: Mechanical Supply and Mechanical Exhaust)

a.1 Provide a minimum of 6 ACH for normal ventilation mode and 10 ACH for fire mode condition.
a.2 Make-up air flow rate preferably 85% of exhaust rate
a.3 Minimum temperature/fire rating of fans: 250 deg celcius/2 hours
a.4 Ducts of 1.2 millimeters (mm) thickness and 2 hours fire rating
a.5 Extraction points for ducted system shall be arranged such that 50% at high level and the other 50% at low level with no part of the floor farther than 12 meters (m) from an extraction. Exhaust air shall be taken at a point within 0.48m of the floor (LL) and ceiling (HL).
(Exemption: Residential apartment buildings shall be permitted without Low Level (LL) extraction points)
a.6 Car park ventilation system employing jet fans confirmed through performance based analysis and use of CFD fire modelling report.

a.6.1 Acceptance criteria for ventilation system employing jet fans
a.6.1.1 at 1.8 meters (m) above floor level and within 10m radius location of the design fire, attains the following:
a.6.1.1.1 Minimum 10 meters (m) visibility upstream of the fire
a.6.1.1.2 Temperature of the smoke layer not exceeding 60 deg celcius
a.6.1.2 Minimum design fire size of 4 MW (2m X 5m) for car parks protected with automatics sprinklers system; 8MW (5m X 5m) for non-sprinklered car parks.
a.6.1.3 Acceptance criteria shall be achieved within 20 mins upon heat/smoke detection.

b. Combination Natural & Mechanical Ventilation Alternative (Arrangement: Natural Supply and Mechanical Exhaust)

b.1 Fixed supply openings of at least 2.5% of the floor area along exterior wall facing a clear unobstructed space outside the building or at least 3 meters (m) minimum.
b.2 Extraction points for ducted system shall be arranged such that 50% is at high level and the other 50% at low level with no part of the floor farther than 12 meters (m) from an extraction point. Exhaust air shall be taken at a point within 0.48m of the floor (LL) and ceiling (HL).
b.3 The velocity of air within escape routes & ramps should not exceed 5 meters per second (m/s) in order to avoid impending the escape of occupants of the building.
b.4 Maximum distance from the fixed opening to the farthest point in the area shall be limited to 45 meters.

c. Natural Ventilation Alternative (Note: For aboveground car parks only)

c.1 Opening of not less than 0.45 square meters (sqm) for each linear meter of ots exterior perimeter distributed over 40% of the building perimeter or uniformly distributed over two (2) opposing sides.

d. Use of Smoke Vents (Note: For 2-connecting basement level from Ground level.)

d.1 Permitted in below ground enclosed car parks whose aggregate floor area does not exceed 1,000 square meters (sqm) and connects 2 basements level only
d.2 Aggregate number and sizes of vents is equivalent to not less than 2.5% of the floor being served, with no vent smaller than 0.6 meter diameter or width
d.3 Vents distributed along perimeter, on side or ceilings of the car park, with no portion on the floor farther than 12 meters (m) to a vent.
d.4 Separate vent provided for each basement level
d.5 Smoke vents which are kept closed during normal or non-fire condition designed to operate automatically
d.6 In car park provided with automatic sprinklers, provision of smoke vents designed such that it does not affect sprinkler activation.
d.7 Vent to be located away from exits.

5. Atrium and other large spaces

a. Designed in accordance with NFPA 90A, 90B, 92 and other QCDD recognized standards provided for atrium or similar communicating spaces that connects more tahn 3 floor levels.
b. Designed in accordance with NFPA 90A, 90B, 92 and other QCDD recognized standards provided to any compartment in the building with floor area of more than 1,000 square meters (sqm)

6. Fire pump room

a. Positive ventilation with fresh air and exhausts directly obtained from external
b. Minimum 6 ACH for normal condition and 10 ACH during fire condition
c. Means of controlling temperature of the room provided.

7. Generator room

a. Positive ventilation with fresh air and exhaust directly obtained from external
b. Minimum 6 ACH for normal condition and 10 ACH during fire condition
c. Means of controlling temperature of the room provided.

8. Fire fighter's smoke control station (FSCS)

a. Located in the fire command center / control room or other location acceptable to QCDD
b. Positive ventilation
c. Means of controlling temperature of the room/equipment provided.

9. Smoke control fan panels

Provides control capability over equipment of the smoke control system
a. On-Auto-Off over individual equipment of the smoke control system that is permitted to or can also be controlled from other sources in the building.
b. Open-auto-close control over individual dampers relating to smoke control system that is permitted to or can also be controlled from other 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 FSCS/panel
d. Switch for manual activation/deactivation or override control of the smoke control system of rotary selector type.

10. Equipment

Equipment such as but not limited to fans, fire dampers, fire-smoke dampers, ducts shall be suitable for its intended use and approved by QCDD.

11. Detection, Control and Activation

a. Fire detection systems required to provide control signals to mechanical smoke control systems or elements thereof shall comply with NFPA 72.
Such detection systems together with its control units shall be listed for smoke control applications
b. Automatic activation of the smoke control system using either of the following:

b.1 Fire alarm system
b.2 Waterflow switch in automatic sprinkler system

12. Power supply system

a. Smoke control system shall be supplied with 2 power sources

a.1 Primary source - from normal building power supply system having separate or independent connection from building's non-fire safety related installations
a.2 Secondary power sources - from an approved standby power supply system complying to NFPA 101.

b. Wiring for operation and control of smoke control systems connected ahead of the main disconnect and protected against exposure to fire
c. Automatic transfer from normal to full standby power within 60 seconds of failure of the primary power
d. Mechanical smoke control system permitted and designed as combined system or which are used to serve both back-up power supply and equipment (standby fan)

d.1 One additional fan required as standby/back-up fan for each system feed by a single fan
d.2 Where a particular control zone is being protected by a system having 2 or more fans or equal capacity, the system could be backed-up by an additional fan having the same capacity of the other fans.
d.3 Where a particular control zone is being protected by a system having more than one fan of different capacities, the system could be backed-up by an additional fan having the same capacity as the largest fan

13. Industrial - Ventilation of workshop and other similar operation / process areas

Storage - ventilation of storage area

a. Reference codes & Standards: NFPA 92, 101 and 204
b. Where required: low and ordinary hazard operation/process area > 450 square meters (sqm) and situated below ground
c. System arrangements:

Natural ventilation
Mechanical ventilation
Combined Natural-Mechanical - natural supply and mechanical exhaust attangement
(Note: mechanical supply and natural exhaust arrangement not permitted)
Smoke Vent

c.1 Negative Pressure in the fire/smoke area; positive pressure in non-fire/smoke adjacent areas
c.2 Separate fan and duct for each fire/smoke area
c.3 Make-up air:

c.3.1 supply points located beneath the smoke layer
c.3.2 flow rate less than the smoke exhaust rate
c.3.3 <1.02 meter per second (m/s) velocity where it could come in contact with the plume

d. Separate manual controls readily accesible for fire department use
e. Direct discharge of contaminated air to external
f. Natural Ventilation Alternative

f.1 Cross ventilation. Openings on opposite sides (note of wind direction)
f.2 Stack ventilation. A.) Openings on perimeter walls; B.) Openings at roof top

***Note. Size, quantity and location of openings shall be such that it meets airflow requirements for occupants, contaminants, smoke and heat dissipation

g. Smoke Vents

g.1 permitted for below ground low and ordinary operation/process areas whose floor area >450 square meters (sqm) up to 2 basement level only
g.2 Aggregate number and sizes of vents is equivalent to not less than 2.5% of the floor being served, with no vent smaller than 0.6 meter diameter or width
g.3 Vents distributed along perimeter, on side or ceiling of the operation/process area, with no portion on the floor farther than 12 meters to a vent.
g.4 Separate vent provided for each basement level
g.5 Smoke vents which are kept closed during normal or non-fire condition designed to operate automatically
g.6 Smoke vent design shall not affect sprinkler activation.

14. Limitations:

Natural or fixed opening shall not be applicable in areas protected with automatic suppresion system (ASS). In order not to impede the operation of the ASS, a mechanical or electrically actuated vents or system shall be used.