Integrity Testing
Also called a Fan Test, Room Integrity Testing (RIT) is related to Gas Fire Suppression systems, and in particular the capability of a room to hold a Suppressant Gas that is discharged inside it. In basic terms it is a way of calculating a leakage rate for a particular room (or enclosure).
The way it works is that the room doorway is blocked off using an adaptable frame and the room is pressurised and de-pressurised using a fan mounted in this frame. Software on a laptop and fan mounted pressure sensors then provide multiple readings measured in air flow and pascals. Once the room volume and gas quantity are added to the software, it can calculate the density of the suppressant gas, and in turn can accurately model room leakage and calculate the Hold Time.
What is the Hold Time?
Hold time for a suppression system is the minimum duration (often 10 minutes) that the extinguishing agent must be held within a protected enclosure at a sufficient concentration to prevent fire re-ignition.
Room Integrity Testing Standards
The main standard that recommends Room Integrity Testing on commissioning of a system and the annual re-testing of an enclosure in the UK is BSEN15004. This UK standard provides guidance on how to carry out the test and the frequency of re-testing.
If you are operating a Gas Fire Suppression System, then you MUST test on commissioning of the system when installed and retest at least annually.
If you have had your RIT carried out, and have failed due to a poor hold time, there are a couple of ways that this can be tackled:
sealing the holes in the room
The easiest way to attack this problem is by sealing the holes in the room. Leakage most commonly occurs:
Around room penetrations
Maybe cable trays/conduit or aircon pipework. This is quite common where a cable tray/conduit/pipe has been installed, breaching the room’s boundary, and not being properly sealed afterwards. Remember that these could be in the floor voids / ceiling voids / cupboards in the room so they may not be obvious at first glance.
Poorly fitting doors/frames
Normally addressed with sealing materials – brush strips etc.
The junction between the walls & floor/ceiling
Sometimes there are long cracks on the joins which can cause leakage – it doesn’t look much, but there may be a lot of it!
Air exchange in the room
If there is air introduced or extracted from outside of the room (for cooling or ventilation purposes perhaps) – these should always be dampened with the dampers closed automatically before the Gas Suppression discharges.
Metal Windows
These are notoriously bad at sealing, especially when getting old or when they’ve been painted numerous times.
Porous Walls (more prevalent in newly constructed rooms and shouldn’t be underestimated)
Porous building materials can allow the suppressant gas to seep through them. Normally PVA sealing and then a couple of coats of paint can fix this issue.
You may have the wrong Suppressant Gas in the room
If tackling the points above is not feasible, then it could well be that changing the Suppressant Gas type may help. Hold Times are dependent upon the density of the Suppressant Gas that is used – so for example, if you have a chemical agent Suppressant Gas such as HFC227ea (FM200), then this is much denser than an Inert Gas blend such as IG55 (Argonite).
A room that may fail to reach its Hold Time on a chemical agent may achieve it by changing to an inert gas.
Avert Fire (UK) Ltd’s trained engineers have the ability to model what the Hold Time would be using different gases in a room following an initial RIT fail and advise accordingly.
Air Permeability Testing
An air permeability test, also known as an air tightness or air leakage test, measures how much air unintentionally leaks through a building’s envelope. This is done by using a specialized fan, or blower door, to create a pressure difference and measure the rate of air leakage. The results are used to assess a building’s energy efficiency, determine compliance with building regulations and guide the necessary ventilation strategy