Room Integrity
Testing Service
Room Integrity testing is a requirement for all fire protection systems that release a gaseous agent to suppress a fire (a Gas Fire Suppression System). An annual Room Integrity Test is a requirement of Australian Standards AS1851-2012 or International Standards ISO/DIS 14520-1. Over time, rooms get modified, resulting in too many penetrations (or leaks) through walls and floors. Testing will locate these penetrations and determine the ability of the room to retain suppression agent in the event of a discharge.
Additionally, Fire System Products’ use of state of the art testing equipment assures that you will receive the most accurate information available. Furthermore, our testing procedure will grant you the confidence to know that your system can respond effectively to a fire emergency. Our team can arrange testing time with minimal disruption to your business.
Why is a Room Integrity Test required?
The primary goal of the Room Integrity Test is to predict the amount of time that a suppression agent is retained in an enclosure or room, should the suppression system be discharged. This is accomplished by performing a Door Fan Test. The Australian Standard AS1851-2012 “Routine service of fire protection systems and equipment” requires annual Room Integrity Testing.
Data centres, electrical rooms and other locations in enclosed space that require gas suppression can have wiring and other openings through walls. These wall penetrations act as potential points where a gas suppression agent can escape. Consequently, this reduces the effectiveness of the suppression agent and potentially resulting in failure to extinguish the fire.
What is the Minimum Retention Time?
Room Integrity Testing ensures the extinguishing agent will achieve the correct concentration and maintains it for a ‘minimum retention time’. The minimum retention time required under AS1851-2012 for all gaseous agents is 10 minutes. Apart from CO2, which has a minimum required retention time of 20 minutes. The ‘retention time’ is the period that the gaseous agent should exist at an acceptable design concentration (Cmin). While remaining above the minimum protected height to prevent the re-ignition of a fire once it has been extinguished.
The ‘minimum protected height’ is a determined height from the base floor level to the top of any identified critical asset or risk designated by the ‘responsible person’. The ‘responsible person’ should always be consulted with and agree to the minimum protected height, regardless.
Calculating the Minimum Retention Time ?
The gaseous extinguishing agent from the Gas Fire Suppression System mixes violently upon discharge, resulting in a homogeneous mixture. Technicians ignore pressures created in the first few seconds of discharge (referred to as dynamic discharge pressure) in the retention time prediction model because they are short. Technicians allow for large factors for loss in the concentration formula.
Descending Interface Case
By shutting off air-moving equipment in the room at discharge, the heavier-than-air agent mixture will tend to stay separate from the air infiltrating through the upper leaks. The Agent will descend to the floor and creates a small positive pressure. The agent/air interface is the intersection between the pool of agent mixture and clean air above. This interface drops as the agent disperses out of the room through leaks in the floor and lower wall area. Air from outside the room generally replaces agent by infiltrating through leaks in the upper half of the room.
Continual Mixing Case
If air-moving equipment is on during the retention period, the infiltrating air will become mixed in with the agent. The concentration of the agent near the floor level will decay at the same rate as the concentration near the ceiling. In some cases, air-flows into or out of the room is due to 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.
Measuring total leaks
The door fan measures total leakage areas and static pressures. Technicians measure Below Ceiling Leaks separately, using a flex duct or plastic on the ceiling to neutralise ceiling leaks. All other variables such as room volume and heights measured on-site. The model predicts how many minutes it will take for the descending interface to reach the minimum protected height. This is specified by the authority having jurisdiction.
How does the Room Integrity Test relate to a discharge test?
The minimum protected height for the descending interface case is 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 designated concentration.
What if the Room Integrity Test fails?
Should the Test fail, we will give you a report and provide a room sealing service. Our trained technicians will perform a leakage test using artificial smoke. Our technicians identify and seal leaks using specialist products and the room retested.
How does it work?
Room Integrity Test Steps:
- Installing the Fan Test Unit in a doorway leading from the protected space to a large open area or outdoors.
- The door fan speed set to provide the same pressure exerted by the agent after discharge, inside the test room.
- Firstly, blowing air out of the room (depressurisation) and secondly, into the room (pressurization). We average the two readings to reduce errors due to:
- HVAC operational. This is a major problem which can vary the results by up to 30%
- Other static pressures. Wind can produce errors by causing the room gauge to fluctuate. 5Pa of fluctuation can vary the results by up to 30%
- One-way leaks. This is rarely a factor.
- We use the air flow needed to create the room pressure to calculate the Equivalent Leakage Area (ELA).
- Therefore, it is very easy to pinpoint exactly where the leakage occurs using a chemical smoke.
- Technicians can predict the time required for the suppressant agent to descend to a given level in the room without having to discharge the actual gas fire suppression system.
Understanding results
The pressure created by the Minneapolis Fan Test Unit causes air to move through leaks at a detectable rate. This pressureusually 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.
Standards require retaining suppressant agents for a minimum of ten minutes within an enclosure or room. This is long enough for most deep-seated fires to cool. Gas suppression systems should provide adequate time for the emergency services to attend, and prevent the fire taking hold.
In summary, the logic for the Room Integrity Testing and survey is to assure property managers and owners that a high level of protection and reliability exist for each hazard area.