The primary cause of the failure of gas fire suppression systems is inadequate room sealing. A Room Integrity Test guarantees your fire protection strategy, provides peace of mind and is a compulsory annual test for Gas Suppression Protected Area.
Researchers have found that rooms get leakier with time, usually due to changes in construction, cabling or services. Therefore, it is essential to ensure good room integrity is established and maintained, particularly bearing in mind the potential consequences of Suppression System failure.
Gas suppression systems are a logical fire suppression solution for rooms containing I.T. or electronic equipment. Unfortunately, these rooms are often the most highly modified in facilities as power, connectivity, and cooling requirements change over time. However, if a room leaks, the fire suppression agent will escape before the fire is controlled effectively.
That is why Australian Standard AS1851-2012 “Maintenance of fire protection systems and equipment” requires an Enclosure Integrity Test each year. The benefits of this are widely recognised by insurers and regulatory authorities, who frequently require testing.
Fire Systems Products technicians are trained and accredited operators of Retrotec Room Integrity Testing equipment. Our commitment to using state of the art testing equipment assures you will receive the most accurate information available. Our testing procedure will grant you the confidence to know that your system can respond to a fire emergency. We are happy to arrange testing of your gaseous protected rooms at convenient times to minimise any disruption to your business.
The door fan itself merely measures the enclosure leakage area and the pressures that may exist across it. In conjunction with the DG-700 Hand Held digital pressure, I-flow gauge, the computer software does the rest of the simulation and comes up with the prediction. The Retrotec CA2001 software walks the user through all the steps in a controlled way to ensure each step is done according to the applicable standard (NFPA, AS or ISO).
The Minneapolis Fan Test Unit is temporarily installed in a doorway leading from the protected space to a large open area or outdoors. The fan speed is adjusted to obtain pressure between the test room and the volume surrounding the test room. This pressure (usually 10 to 15 Pa or 0.04” to 0.06” W.C.) is similar to the steady-state pressure (column pressure) exerted by the gaseous extinguishing agent at floor level at the start of a typical 10 minute retention period. The pressure created by the Minneapolis Fan Test Unit causes air to move through leaks at a detectable rate. The leaks are usually straightforward to pinpoint precisely where they occur using chemical smoke.
The door fan pressurises the enclosure to the same pressure exerted by the agent on the floor after discharge. The flow needed to create this pressure is used to calculate the leakage area of the enclosure. By measuring the airflow rate and the pressure created, the computer software calculates the Equivalent Leakage Area (ELA), or the total area of all the cracks, gaps, and holes in the test room. The flow pressure across the blower inlet is converted into flow by computer software. The door fan pressurises the enclosure to the same pressure exerted by the agent on the floor after discharge.
The flow needed to create this pressure is used to calculate the leakage area of the enclosure.
First, the measurement is done by blowing air out of the room (depressurisation) and then into the room (pressurisation).
The two readings are then averaged to reduce errors due to:
HVAC operation-major problem can produce 30% errors
Other static pressures. The wind occasionally can produce errors if the room gauge is fluctuating. 5Pa of fluctuation will produce a 30% error
One-way leaks-almost never a factor in how the retention time Is calculated.
The gaseous extinguishing agent mixes violently upon discharge resulting in a homogeneous mixture. Pressures created in the first few seconds of discharge (referred to as dynamic discharge pressure) are ignored in the retention time prediction model because they are so short and because large factors for loss are already allowed for in the concentration formula.
The heavier-than-air agent pressing down upon the floor creates a small positive pressure. Flow develops whenever a hole has a pressure difference across it. The greater the pressure and the larger the hole, the greater the agent lost. A small negative pressure will develop at the top of the room that will allow a similar volume of air to flow back into the room from leaks at the higher elevations.
If air-moving equipment in the room is shut off at discharge, the agent mixture will tend to stay separate from the air infiltrating through the upper leaks. The intersection between the pool of agent mixture and clean air above is referred to as the agent/air interface. This is called the descending interface case. This interface drops as the agent is lost out of the room through leaks in the floor and lower wall area. Air from outside the room generally replaces the agent by infiltrating through leaks in the upper half of the room.
If air-moving equipment is left on during the retention period, the infiltrating air will become mixed in with the agent. This is called the continual mixing case. The concentration on the floor will decay at the same rate as the concentration near the ceiling. In some cases, airflow into or out of the room is created by other causes (e.g. damper or duct leakage). This airflow produces a static pressure, which pushes the agent out faster. This static pressure is, therefore, usually eliminated. The door fan measures total leakage areas and static pressures.
Below ceiling leaks can then be measured separately using a flex duct or plastic on the ceiling to neutralise ceiling leaks. All other variables such as room volume and heights are easily measured on-site. The model predicts how many minutes it will take for the descending interface to reach the minimum protected height specified by the Authority Having Jurisdiction or the concentration to fall to the minimum percentage acceptable for the continual mixing case.
How the door fan test relates to a discharge test:
The minimum protected height for the descending interface case is usually chosen at the same place where the highest acceptance sampling probe would be located.
The less common continual mixing case is equivalent to the minimum allowable design concentration.
The Room Integrity Testing and survey logic is to assure property managers/owners that an appropriate level of protection and a high level of reliability exists for each hazard area.
While this report sets out some recommendations for improving the level of fire protection for some particular areas in the facility it is also important to note that the fire protection systems and equipment need to be properly managed and maintained to ensure their performance and reliability when required some particular areas in the facility it is also important to note that the fire protection systems and equipment need to be properly managed and maintained to ensure their performance and reliability when required.
Contact Fire Systems Products on +61 (02) 8004 9156 to discuss your Room Integrity Testing requirements!