AS1851 Section 18 - Smoke Management
Australian Standard 1851 ? Maintenance of Fire Protection Systems and Equipment, has been comprehensively revised. The new standard, AS 1851- 2005, was published in September by Standards Australia after a ten year development period that included extensive industry consultation.
A single dedicated fire protection committee, called FP001, was formed to create the standard, rather then individual fire committees as has been the case over the past 30 years. Group manager for construction and fire services at Standards Australia, Karen Hitchiner, says this was an important change that arose after industry consultation.
Also following consultation, the new standard has been packaged in a much more streamlined form. Where AS 1851 was separated into 16 parts, the new version has been written as an al-in-one document, providing a more concise and user-friendly approach to fire and smoke protection.
The rationale behind the overhaul was straightforward enough. The existing standard, involving periodic inspections of systems and equipment in isolation, was deemed an insufficient and impractical method of making sure everything was in working order.
Systems interface testing
The new standard, when applied, will ensure all systems and equipment interface effectively at all times, so that if a fire ever does break out there will be minimal risk of a systems failure leading to disaster. The new imperative to inspect ''systems interfaces'' ? how the various fire and smoke protection systems and equipment interact with one another ? means fire detection and alarm systems must be checked to ensure they activate fire protection equipment such as sprinklers, stairwell pressurisation fans and smoke curtains, and all systems must be checked to ensure they operate in isolation and in concert.
''Since all fire systems only work if there is a fire, there is a fundamental need to test them? at least once a year to make sure they actually work. Typically, different engineers do not check the whole system, so this new standard is making a big issue of testing the interfaces between the entire fire protection system to make sure they work,'' says Simon Hill, chairman of Standards Australia?s committee on fire and smoke control and AIRAH fellow.
Hill oversaw development of Section 18 of the Standard, which details maintenance of fire and smoke control equipment for HVAC systems. He says Section 18 of the new standard incorporates most of the details of the old standard, last published in 1997 and previously known as AS 1851.6, but contains some important additions. Three new tests have been included in the standard alongside the existing tests for stairwell pressurisation and changeover systems (the changeover of air conditioning from comfort mode to fire control mode).
Testing of smoke exhaust systems for large spaces or atria, shutdown systems for buildings with multiple fans, and smoke damper inspections, have been added to the testing regime. Provisions for remote monitoring of systems and equipment are another important revision, and one that recognises the increasingly central role technology can play in today?s inspection processes.
Previously, monitoring fans for vibration or overheating required a ''sensory'' inspection involving sight, touch, hearing or smell. According to Hill, the sensory method is perfectly appropriate for inspecting smaller fans but may not be for large ones, and could even be dangerous in a situation where a fan needs to be inspected while switched on. ''The (new) standard sees diagnostic procedures or remote monitoring as an acceptable alternative to sensory methods. We?re allowing modern technology to be used to monitor devices that for reasons of safety or lack of access could not otherwise be checked,'' Hill says.
Logbooks and Monitoring
The prevalence of building automation systems today has also been accounted for in the new standard, which recognises that systems tests can in many cases be conducted electronically. The computer that runs the building can fire up all of these systems in smoke mode once a week or whenever and record automatically, by means of pressure switches or indicator lights. That gives you a level of certainty that plant will run, even more than if you do your monthly or six-monthly testing,'' he says. One procedure where technology has not replaced the old methods, however, is data storage. Paper records of maintenance work are still essential.
While the new standard recognises many building managers and contractors keep electronic records of data these days, it is required that hard copy maintenance records are kept onsite too for greater accuracy and access.
Hill says there are two important reasons for this ? so third parties, such as fire brigades and insurers, can verify that maintenance has been properly undertaken in the event of a fire, and so that if a disaster or fatality were ever to occur, records would be available for a coroner?s inquest.
Testing systems and equipment now involves four systematic steps; '''inspection, test, preventive maintenance, and survey'''. The new addition of a ''survey'' involves a ''visual inspection, to identify if fire protection systems or equipment have been altered, damaged or compromised in any way since the previous inspection, test, or maintenance activity,'' according to Hitchiner.
Reporting now involves answering a more concise series of yes/no questions, rather than merely ticking a box. ''These forms are comprehensive, and include all the items one would expect to have in a test. (They) have been developed in real world situations, and are practical guides for recording the results of maintenance, inspections, tests and surveys,'' Hill says.
According to Hitchiner, any critical defects likely to result in failure must be reported immediately for prompt rectification, so ensuring continuity of performance and operation. She says the new standard includes an annual ''clear outcome'' condition report, a document drawn up by the building owner detailing completion of all maintenance activities and certifying that systems have been maintained according to the standard, and listing any defects.
Qualification of technicians
The new standard also recognises that inspection and maintenance of systems and equipment calls for the judgement of qualified HVAC technicians to ensure accuracy. To this end, it includes three voluntary skill level ratings for personnel, as a guide for who is qualified to undertake maintenance work and inspections.
The lowest level of ranking is that of a non-technical employee who nevertheless has demonstrated knowledge of the standard and has gained a few years of supervised experience working with fire protection systems and equipment. These people are qualified to carry out basic inspections such as checking outdoor air intakes for accumulated rubbish.
The second level is occupied by qualified technicians with demonstrated knowledge of the standard and other standards related to HVAC systems.
The highest level is the specialist category, and includes qualified engineers with a minimum of five years? experience, or a diploma and at least seven years? experience, or trade qualifications and at least 12 years experience.
These three skill levels for inspection and maintenance are unique to the HVAC component of the standard.
The new standard addresses advancements in the technology of fire protection and changes in practice in recent years. Fire protection equipment that did not exist or was less commonly employed than today and did not feature in any previous standard has been included in testing regimes.
After a comprehensive overhaul, the list of equipment that now falls under the standard includes; '''fire dampers, smoke curtains, operable windows and shutters, variable frequency drives, pneumatic compressor and receiver stations, motor control centres, main switchboards, fire indicator panels, and fire fan control panels'''.
Hill says that while not all of these features are specifically related to HVAC systems, they have all been placed within Section 18. The standard also recognises the growing number of passive ventilation systems.
Hitchiner says Section 17 of the standard has been expanded from eight pages to 32, and places great emphasis on passive elements of construction. In another positive concession to conservation, weekly inspections of fire sprinklers and pump sets have been eliminated and replaced with a monthly inspection regime, as a water-saving measure. Standards Australia estimates this change could save as much as 75% water compared to the old standard. Any critical defects likely to result in failure must be reported immediately for prompt rectification
AS 1851-2005 is now available from Standards Australia. More information can be found at http://www.sai-global.com