Gaseous Extinguishants.

Gaseous extinguishants are often used to protect sensitive equipment and documents that should not be exposed to water. Banks major businesses IT companies, and institutions using sensitive equipment or information have these installed to minimize there exposure to risk.

Installed by specialist companies these systems effectiveness is dependant on the integrity of the enclosure they are protecting whether it be a large building or a small server room.

The integrity of the building, structure or room can change with the installation of 1 cable. It is therefore required the integrity is checked periodically.

Integrity testing

The 'integrity' of an enclosure is its capability to retain an extinguishing agent.
It is crucial that a fire protection system operates to the best of its ability and is effective. To do this, adequate containment of the extinguishant within the risk area is essential and it is therefore a requirement that integrity testing is carried out on a regular basis either when works have been carried out to the enclosure or at least on and annual basis.

The test is environmentally friendly and does not involve the discharging of extinguishant.

A written report is issued on completion of each test and a certificate issued if a positive result is achieved. This certificate is valid for one year unless changes have been made to the room, equipment or extinguishant, during the year. If any of these have occurred then a retest should be undertaken after all works have been completed.

If a test indicates failure to meet the required retention time then a survey is carried out noting leakage areas. A report is then submitted indicating remedial sealing works envisaged to possibly achieve or improve results.

Airtight can undertake tests in accordance with NFPA 2001 or ISO 14520.

Remedial works

Airtight engineers have been carrying out intergrity tests throughout the world for over 15 years. Through experience we are able to identify areas which are likely to be the cause of the failure. We can also undertake smoke audits to show the areas of leakage.

The majority of test failures are caused by the lack of enclosure integrity or the ability of the enclosure to adequately retain the extinguishant. The correct initial design concentration is achieved but the enclosure is not able to retain it for the required/ recommended holding period.

Remedial work should then be undertaken to reduce the leakage from the enclosure. This could include;

• Sealing all holes, cracks or penetrations leading into or out of the protected space
• Pipe chases and cable trays to be sealed around the outside and inside where they penetrate the perimeter boundaries of the enclosure
• Walls to be caulked around the inside perimeter at both high and low level
• Sealing of porous block walls
• Addition of door sweeps or drop seals, weather stripping around jambs
• Sealing of windows/glazed sections to the area

Once the appropriate remedial work has been undertaken then the enclosure should be retested to confirm if an acceptable level of integrity has been reached.

Airtight are able to quote and instruct engineers to undertake remedial works if required.

Pressure relief

Certain enclosures achieve a positive result indicating that they are adequately sealed for agent retention and are capable of effectively retaining the extinguishant.
However, when high volume extinguishants are utilised, large volumes of air are displaced by the inerting agent and this can give rise to pressure spikes occurring if not counteracted. Hence the requirement, in some instances, for pressure relief.
Pressure relief vents should be installed if there is any doubt in this element and these are normally closed, allowing no back flow of air from the outside to enter the protected area. However, during the release of the extinguishing agent the pressure relief vent would open to vent off excess pressure and then close, maintaining the fire integrity of the room and allowing the safe displacement of air.

Airtight can supply advice/quotations for the supply of vents and for their fitting if required.