Why Clean Agent Systems?
Liquid-based suppression systems provide only a minimum amount of fire protection. For critical company information systems, data centres, paper archives, museums and other enclosures whose contents are susceptible to water damage, sprinkler systems will indeed protect the building from fire damage, but at the expense of the contents being protected! It was due to this necessity to provide sufficient fire protection for the building and also to mitigate or eliminate damage to the contents that non-water-based suppression systems were introduced.
Halon was one for the first of these fire suppressants. Halon (and other gaseous systems) presented a new problem to the designer however; to extinguish a fire and to keep it suppressed, the gas needed to be present in the enclosure for many minutes.Enclosures now had to be tight” enough to retain the Halon in sufficient concentration and for sufficienttime to ensure that re-ignition did not occur
The Discharge Test
Prior to 1988, the capability of an enclosure to retain its fire suppressant was assessed by a Discharge Test. Sensors (detectors) that detected fire suppressant concentration were installed at various points of interest around the room and then the fire suppressant system was discharged. During the discharge, these sensors where monitored. A room would pass or fail the test by examining the agent concentration at the top of the equipment over time. The room passed the test if sufficient agent concentration was present after the required hold time at the top of the equipment. In theevent that the room failed, usually the only recourse was for a sealing job to be undertaken and then, for the discharge test to be repeated.
Aside from the cost of repeated discharge tests, Halon, the predominant agent at the time, was also known to be an ozone depleter. In 1989 the EPA mandated the industry to eliminate all future Halon discharges for the purpose of enclosure integrity verification.
Even today, the discharge test is of limited use due to:
1) High Cost: Costs of labour and product to repeatedly recharge system is high.
2) Disruption: Discharge test is very disruptive to occupied enclosures.
3) Failure Identification: In the event of failure, the discharge test offers no opportunity to identify leak locations.
4) Repeat Testing: Although the Standards encourage annual retest, the above factors virtually preclude any retesting.
The Door Fan Test
Towards the end of the discharge era, several progressive installers found a unique way to ensure that they would always pass the discharge test. They used a fan mounted in a doorway to create pressure which in turn allowed them to locate hidden leaks using chemical smoke. When the leaks were sealed, the room would always pass the discharge test. It worked so well that the discharge test has now been replaced by the Door-Fan Test.
NFPA 2001, NFPA 12A, and ISO 14520 now all require an enclosure integrity test as part of the acceptance procedure for all clean agent systems, including all halocarbon and inert gas agents. This comprehensivetest and calculation procedure predicts how long the agent will stay in the room if it were ever discharged.
The Enclosure Integrity Test’s primary goal is to predict the enclosure’s retention time
In the event that the Clean Agent Fire Suppression System is discharged. The discharge test typically only verified agent distribution in one location, usually the most favourable. This often led to assuming that other approval steps for the enclosure could be overlooked. To make matters worse, the discharge test was never repeated. The room leakage would increase steadily, compromising the system from day one.
The Enclosure Integrity Test’s simplicity and accuracy, encourages trouble-shooting of problem rooms and retesting either periodically or after enclosure modification. In the past, enclosures were often designed merely to pass the discharge test. This often left rooms with fire barriers on only 5 sides and with the top completely open. Often only ceiling tiles stood between the protected enclosure and an adjacent unprotected area! Smoke or fire could readily enter from above.
Enclosure Integrity Test
The best way to ensure that the enclosure is protected from smoke events occurring OUTSIDE of the protected room!
Now, the EPA, Industrial Risk Insurers, Factory Mutual, other insurers, Fire suppression equipment manufacturers, and the FSSA all encourage Door-Fan tests on every installation. Both NFPA and ISO require Door-Fan tests to be repeated every 12 months, or whenever new holes are made in the enclosure.
What is a Door-Fan test?
The Door-Fan Test measures the size of holes in the enclosure using a door-fan to pressurize the room to the same pressure it would experience during discharge. Knowing the pressure inside the enclosure, the pressures across each wall, and the flow through the door-fan to maintain the enclosure pressure, a computer calculates the retention time.
Total Room (Whole Room) Leakage
Using a single door fan / multi fan to pressurize the room will measure the total leakage area of the entire room; floor, walls, and ceiling. This result is called the Whole Room or Total Room Leakage.
Because this measurement includes the leakage in upper area of the room, where the agent would not normally leak out, it often results in unrealistically large leakage and unrealistically short retention times. A room which passes a Whole room test would most certainly pass a discharge test. A room which fails the Whole Room Test however, might very-well pass a discharge test if the majority of leaks were at ceiling level.
When conducting a Total Leaks Test, a single / Multi door-fan is temporarily installed in a doorway leading from the protected room to a large open area or outdoors. The fan speed is adjusted to obtain a pressure difference between the test room and the volume surrounding the room. This pressure (usually 10 to 15 Pa) is similar to the steady state pressure (column pressure) exerted by the agent at floor level immediately after discharge. The computer converts flow and pressure readings into an Equivalent Leakage Area (EqLA), the total area of all the cracks, gaps, and holes in the room.
Overview Features
Enclosure Integrity testing software with automated report generation developed by Retrotec to improve the user experience when performing tests. With an intuitive user interface, test setup and data entry is simple. It seamlessly calculates results in compliance with the most recent editions of all recognized gaseous fire suppression system standards.
Software to record readings from a fan and manometer set up to measure air leakage in an enclosure, and calculate results for agent retention time and peak pressure during hold time based on the measured air leakage. The software can automatically calculate results in accordance with a number of standard enclosure air leakage testing procedures. The software will generate a report containing measured and calculated results in accordance with the chosen standard testing procedure.
Fully compliant with the calculations in the latest standards (NFPA2001 -2012, ISO14520-2006, EN15004-2008)
Record data from your enclosure integrity tests and let FanTestic Integrity calculate all the results and determine if the enclosure passes or fails.
Calculate peak pressure in an enclosure and vent area needed based on measured air leakage
Test installed pressure relief vents to verify that the venting area is enough to maintain the enclosure structural integrity
Calculate additional venting required, if over the measured air leakage
Graphing – see the readings and calculated results visually on a graph
