IFSECInsider-Logo-Square-23

Author Bio ▼

IFSEC Insider, formerly IFSEC Global, is the leading online community and news platform for security and fire safety professionals.
August 23, 2010

Sign up to free email newsletters

Download

Whitepaper: Multi-residential access management – The move to digital

Smoke control systems – typical maintenance issues

When considering life-safety systems such as smoke control, preventative maintenance is crucial and a legal requirement, says Will Perkins.

enginer and panel

Preventative maintenance of systems is crucial

 

Smoke control systems should be maintained on a six-monthly basis to ensure that all components are fully functional and perform to the original design specification for the building, by providing continued reliability in the event of a fire. This preventative smoke control maintenance is required by BS 9999 and BS 7346-1 Components for Smoke and Heat Control Systems. Specification for natural smoke and heat exhaust ventilators. In addition, the Regulatory Reform (Fire Safety) Order 2005 outlines considerations and requirements for fire safety measures, which include maintenance of fire safety systems and equipment.

In many apartment buildings, it is assumed that a fire is most likely to occur in an apartment. The principle is for the occupants of the apartment or apartments affected by fire to escape immediately, while other residents stay put until the arrival of the fire and rescue service. As the occupants of the ‘fire’ flat escape, however, it is probable that some smoke will get into the common corridor or lobby. It is therefore important to ventilate this smoke to prevent it getting into the common stair, and it is the protection of this common stair that is the primary objective. This ventilation also affords some protection to the common corridors/lobbies but this is a secondary benefit – not a primary requirement.

To ventilate this smoke from the corridor or lobby, Approved Document B recommends that if an external window is located on the external wall an Automatic Opening Vent (AOV) can provide effective smoke ventilation. But typically developers use external walls for apartments to create a scenic view for the occupants. In this situation a vertical smoke shaft is provided with either an automatic opening smoke shaft door or damper opening into the smoke shaft and exhausting the smoke into the smoke shaft and out through the top of the shaft, via an AOV.

On the ceiling of each landing or lobby is a smoke detector which, when activated, simultaneously triggers the opening of the corridor or landing AOV, smoke ventilation shaft roof AOV and escape stair AOV. Once opened the system ensures no other doors on the smoke ventilation shaft can be opened, ensuring smoke does not transfer between floors.

building exterior
In apartment buildings, the priority is to keep escape stairs clear of smoke

Typical maintenance
In maintaining these systems, the smoke detectors are subjected to tests via a telescopic smoke testing unit – each sensor should then operate the corresponding AOVs. This is repeated on each floor after resetting the system. Every 12 months the smoke detectors are cleaned to reduce contamination and false alarms.

To ensure that motorised AOVs do not present a ‘trap hazard’ when closing, switches adjacent to them have to be remain depressed to keep the closing operation going. In other words, the mechanism must stop as soon as the switch is released. This configuration is known as a mitigating the risk of the trap hazard to a passing occupant. All AOVs within 2.5 m of floor level must have some form of ‘mitigating procedure’ or safety device fitted and checking these forms part of the inspection.

Following inspection of the system in action, all AOVs, including the doors, windows and roof vents are inspected for signs of wear and tear, and fixings are checked then lubricated and cleaned if necessary. Any parts requiring replacement are duly noted on a report. Reports are then passed to the managing agents, who often look after the building on behalf of the owner. Where failures have occurred during inspection the managing agents would agree a course of repair.

On many installations a repeater panel is installed as part of the smoke ventilation system and is typically be located near the fire service access entrance of the building, to provide system indication. This provides essential system information for the fire service, client and maintenance engineer.

Components are checked and lubricated

The repeater panel indicates green lights to show the system as being healthy, a red light shows that the system has been activated on a particular floor or in a specific zone, and an amber light indicates a fault. Should an amber light or red light remain present on the panel, the maintenance engineer should be called out to undertake a reset or a repair.
Within the control panel a 24V battery back-up supply is provided which will continue to operate the smoke ventilation system in the event of a mains supply failure. During maintenance visits, batteries are checked for performance and recommended for replacement where they fall below a certain standard. Batteries last on average 3 to 5 years.

The extra mile
So far we have discussed the routine maintenance and repair of systems, but the maintenance engineers’ responsibilities go a little further. Occupiers of a building can often unknowingly influence and compromise the correct working of smoke ventilation systems. One of the most common potential problems is clutter.

For example, vertical smoke ventilation stacks are fitted with grilles at each floor level to ensure safety when access doors are opened. But these grilled areas have sometimes been used as storage areas by residents, so potentially compromising the operation of an access door in the event of a fire. Roof light openings can also be compromised by items placed on or near them. Penthouse occupiers can unknowingly cause problems with trees and shrubs which will interrupt the opening of the roof light, and could lead to a build up of smoke in an incident. These issues are recorded by the maintenance engineer and again it is up to the managing agents to advise the occupier of the issues and agree a course of action.

As systems become more intelligent and more cost effective to install, cable management and self diagnostic systems are now emerging. Using a much simplified wiring system with less connecting wire, these systems monitor motor speed and resistance to determine the correct operation of the device. Should the ‘load’ profile change, this would indicate a fault and would initiate a call out. SE Controls have developed ‘OSLoop’ which works on this principle. Each zoned area can be linked and where a cable fault or incorrect voltage of the actuation is detected, a maintenance engineer can be called to rectify the problem in the particular area. These more advanced systems meet the required standards of the forthcoming EN 12101- 9 and 10, Control Panels and Power Supplies.

Will Perkins is managing director of SE Controls, who offer a complete service from design through to maintenance of smoke control systems www.secontrols.com or tel 01543 443060.

Subscribe to the IFSEC Insider weekly newsletters

Enjoy the latest fire and security news, updates and expert opinions sent straight to your inbox with IFSEC Insider's essential weekly newsletters. Subscribe today to make sure you're never left behind by the fast-evolving industry landscape.

Sign up now!

man reading a tablet, probably the IFSEC Global newsletter

Related Topics

Subscribe
Notify of
guest
1 Comment
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
JamesSimon1
JamesSimon1
April 8, 2015 4:48 am

I’ve had my smoke alarms go off several times falsely. Usually, it’s when they’re mounted next to the bathroom and the steam from the shower trips them off. Then again, they are an older model so I can see that being a problem.
http://www.fireprotectionservices.com.au/service__maintenance