Pressurization System

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What is a Pressurization System

 

A staircase pressurization fan forces clean outside air into a stairwell when there is a fire. The staircase pressurization’s role is to push smoke back and keep it out of the escape route. This allows building occupants to escape safely without smoke intoxication during the event of a fire.

 

For staircase pressurization to work, the stairwell must have a higher pressure than the rest of the building during a fire. The minimum pressure difference is 50 Pa [1]. When the doors open, the staircase’s higher pressure forces the smoke back, ensuring that the escape route is free of smoke.

 

When a fire occurs, a signal will be sent to the fire alarm panel. Then, the fire alarm panel will activate the staircase and lift lobby pressurization fans to turn on and start pressurizing the protected areas.

 

Applicable Codes and Standards

 

In Malaysia, pressurized lift lobbies are required if the building has a height of 45 metres according to Section 197 of UBBL 1984. Meanwhile, staircases are required to be pressurized if the building height is more than 45.75 metres according to Section 202 of UBBL 1984. The excerpt of these sections is shown below.

 

Section 197. Protected lobbies [1].
(1) Protected lobbies shall be provided to serve staircase in buildings exceeding 18 metres above ground level where the staircase enclosures are not ventilated through external walls.
(2) In buildings exceeding 45 metres above ground level, such protected lobbies shall be pressurised to meet the requirements of Section 7 of the Australian Standard 1668, Part 1 1974 or any other system meeting the functional requirements of the D.G.F.S.
(3) Protected lobbies may be omitted if the staircase enclosures are pressurised to meet the requirements of the by-law 200.

 

Section 202. Pressurized system for staircases [2].

All staircases serving buildings of more than 45.75 metres in height where there is no adequate ventilation as required shall be provided with a basic system of pressurization
(a) where the air capacity of the fan shall be sufficient to maintain an air flow of not less than 60 metres per minute through the doors which are deemed to be open;
(b) where the number of doors which are deemed to be opened at the one time shall be 10% of the total number of doors opening into the staircase with a minimum number of two doors open;
(c) where with all the doors closed the air pressure differential between the staircases and the areas served by it shall not exceed 5 millimetres water gauge;
(d) where the mechanical system to prevent smoke from entering the staircase shall be automatically activated by a suitable heat detecting device, manual or automatic alarm or automatic wet pipe sprinkle system;
(e) which meets the functional requirements as may be agreed with the D.G.F.S.

 

Ventilation of Staircases

 

Sections 198 to 200 of UBBL 1984 issues instructions on the ventilation types for various staircase heights.

 

Section 198. Ventilation of staircase enclosures [3].

(1) All staircase enclosures shall be ventilated at each floor or landing level by either permanent openings or openable windows to the open air having a free area of not less than 1 square metre per floor.

(2) Openable windows shall meet the operational requirements of the D.G.F.S.

(3) In buildings not exceeding three storeys above ground level, staircase enclosures may be unventilated provided that access to them at all levels except the top floor is through ventilated lobbies

 

Section 199. Ventilation of staircase enclosures in buildings not exceeding 18 metres [4].

In buildings not exceeding 18 metres above ground level, staircase enclosures may be unventilated provided that access to them at all levels except the top floor is through ventilated lobbies and the staircase enclosures are permanently ventilated at the top with least 5% of the area of the enclosures.

 

Section 200. Ventilation of staircase enclosures in buildings exceeding 18 metres [5].

For staircases in buildings exceeding 18 metres above ground level that are not ventilated in accordance with by-law 198, two alternative methods of preventing the infiltration of smoke into the staircase enclosures may be permitted by providing

(a) permanent ventilation at the top of the staircase enclosure of not less than 5% of the area of the enclosure and in addition at suitable intervals in the height of the staircase a mechanically ventilated shaft to achieve not less than 20 air changes per hour to be automatically activated by a signal from the fire alarm panel; or

(b) mechanically pressurisation of the staircase enclosure to the standard of performance as specified in section 7 of the Australian Standard 1668, Part 1 1974 or any other system meeting the functional requirements of the D.G.F.S.

 

The following table shows a summary of sections 198, 199 and 200 of UBBL 1984.

 

Summary of UBBL Section 198, 199 and 200 on Staircase Ventilation

 

Our M&E Consultant Solutions

 

As M&E consultants, our solutions for Pressurization System include:

  • Design of staircase and lift lobby pressurization system for BOMBA Authority approval
  • Schematic design of staircase and lift lobby pressurization system for BOMBA Authority approval
  • Professional Engineer drawing endorsement

 

Perunding JW is an M&E Consulting firm based in Malaysia. If you are looking for more information or resources, reach out to our team of engineers. We will gladly assist you. Visit our homepage or call us at +603 7955 5918.

 

References

[1] Street, Drainage And Building Act 1974 [ACT 133] Uniform Building By-Laws 1984, vol. 197. 1985.

[2] Street, Drainage And Building Act 1974 [ACT 133] Uniform Building By-Laws 1984, vol. 202. 1985.

[3] Street, Drainage And Building Act 1974 [ACT 133] Uniform Building By-Laws 1984, vol. 198. 1985.

[5] Street, Drainage And Building Act 1974 [ACT 133] Uniform Building By-Laws 1984, vol. 199. 1985.

[6] Street, Drainage And Building Act 1974 [ACT 133] Uniform Building By-Laws 1984, vol. 200. 1985.

Hose Reel System

Hose Reels are meant for occupants to fight fire in its early stages.