.2 Software Conformance
Analysis tools in use by the technician to produce ELA and retention time calculations must conform to the standard being tested to (either NFPA or ISO). Retrotec’s HA6 DOS software and CA2001 Windows software conform to the NFPA 12A and 2001 standards exactly.
CA2001 conforms to the ISO 14520 standard exactly.
.3 Room Pressure Gauge Calibration Certificate
The NFPA standard requires that the pressure gauge used to measure the room pressure be calibrated annually. Experience shows however that unless the gauge has been damaged or moves unevenly it is generally within 10%.
Calibration certificates for each piece of equipment are stored within CA2001. The witness should ensure that the gauge being used by the technician has a current calibration certificate within CA2001 and that the serial number on the gauge matches the serial number in the software.
The ISO standard recommends calibration but does not suggest the interval. It does require +/- 1% accuracy. Retrotec recommends annual calibration of all pressure gauges.
.4 System calibration
The NFPA standard requires that the complete door-fan system be calibrated every 5 years. Calibration certificates for each piece of equipment are stored within CA2001. The witness should ensure that the blower (or blowers) being used by the technician has a current 5-year calibration certificate within CA2001 and that the serial number on each blower matches the serial number in the software.
.5 Field Calibration check procedure
A field calibration check can be requested by the witness to see if the equipment and operator can actually measure a hole of a known size. This test takes very little time to perform and is the perfect way to gain confidence in the tester, test equipment, and test technique.
It is preferable to inform the operator beforehand of the expectation to perform a field calibration check so the operator can bring the requisite equipment.
.6 Return Path
There must be a complete and unobstructed flow path from every leak in the enclosure back to the Door-fan otherwise some leaks may not be measured. This may entail opening stairwell or elevator doors to floors above and below, neighboring room doors, and perhaps windows and doors leading outside (if the enclosure under test borders an external wall).
The witness should ensure that the operator has examined and accounted for the return paths from all leaks.
.7 Room and Equipment Set-up
All doors within the zone must be open. The HVAC system and all dampers must be set as they would be at or during a discharge. A doorway must be selected that opens into the largest and most open space. Applying tape to seal up the Door-fan panels is OK as long as the doorway is tighter than the panels. The volume of the room should be calculated on-site using a tape measure or by counting tiles. Taking volume measurements from blue-prints or site-staff as gospel, without confirmation, should not be permitted.
Maximum agent height and minimum protected height must be physically (and correctly) measured on-site. Similarly, the operator must confirm the weight or volume of agent through actual inspection of the bottles, not by consulting design documents or talking to site staff.
.8 Static Pressure Check
Before beginning the test, the operator should accurately determine the static pressure. With the doorway completely sealed and the door-fan completely sealed, the magnitude of the static pressure must be measured. By opening a small hole (perhaps a single low-flow plug) and using smoke, direction of the static pressure should be determined. Relying on the positive/negative sign as read from a digital gauge is very error-prone and should be discouraged. The origin of pressures above 3 or 4 Pa should be determined and rectified if possible.
.9 Gauge Set-up
In the case of analog gauges, gauge leveling and zeroing must be completed before any tubes are hooked up. Most analog gauges are meant to be mounted vertically (usually on doorframe or in a pre-designed rack or console). Once mounted, the gauges should be carefully zeroed using small screw-driver and tapped gently to ensure stability. Once zeroed, analog gauges should be quite stable over the course of the test and need only be spot-checked occasionally or tapped prior to each measurement.
In the case of digital gauges, zeroing is usually done through a pneumatic switch, either manually or automatically. Many digital gauges are susceptible to position and once zeroed, should not be moved. Digital gauges also tend to drift slightly over time as they warm up. Digital gauges should be zeroed prior to each test measurement. The witness should ensure that gauges are zeroed correctly.
.10 Flow and Room Pressures Entered Correctly
In addition to ensuring that the gauges are correctly reading the pressures, the witness should also confirm that the operator actually records the pressure correctly and enters it correctly into the software.
.11 Range Selection
The “Ranges” on a Retrotec door-fan refers to the selection of flow-restrictor-plates or orifices that change the airflow through the blower. Testing on the correct Range is extremely critical for good results for two reasons.
Often the same room-pressure can be achieved with a number different Ranges (just like a manual transmission car can achieve the same speed in a number of different gears). For the best results, the door-fan should be running above ½-speed and the flow-pressure through the door-fan must be greater than the room-pressure and should be at least double the room pressure. If these conditions aren’t met, the operator should change to the next smaller flow range.
If the operator does not input the correct flow-range that the test was conducted on into the software, the results can be significantly affected. Retrotec’s CA2001 Windows software displays a picture of the selected Range, which must be acknowledged, before the results of each test are entered. On older versions of software, the ranges can only be identified by consulting a pictorial table.
The witness must confirm that the range on the printout or shown in software during the test matches the range that is actually used by the operator.
.12 Testing in Both Directions
Rooms must be tested positively and negatively to eliminate bias due to duct leaks and other static pressures. Testing in both directions is not done due to positive pressures after discharge.
.13 Determining the Leakage Split – The BCLA Test
To measure leaks in the lower part of the room is not the same as taping up leaks to pass a discharge test. The leakage of the whole room, including the ceiling is measured in the first test, the Total Leaks Test. The lower leaks can be measured separately to get a more accurate prediction of retention time. The Total leaks test MUST be performed first and then, and only then, can the BCLA test be performed.
During a ceiling-neutralization/flex-duct test, the witness should ensure that the operator has indeed neutralized smoke flow across the ceiling. Smoke must be used in this test as equalizing pressures using a gauge is not adequate.
.14 Technical Judgment
As a last resort to other BCLA techniques, Retrotec software has a spreadsheet method of determining leak location. For enclosures with extremely large overhead leaks they may be passed using “technical judgment” as per the following section:
Section C-1.2.2 (e) of NFPA 2001 App C version 2000 states:
“Enclosures with large overhead leaks but no significant leaks in the floor slab and walls will yield unrealistically short retention time predictions. Experience has shown that enclosures of this type can be capable of retaining clean agent for prolonged periods.
However, in such cases the AHJ might waive the quantitative results in favor of a detailed witnessed leak inspection of all floors and wall with a door fan and smoke pencil.”
It must be understood that, although this test will show the enclosure’s ability to hold agent in a discharge test, a large measure of the passive fire protection has been eliminated due to the absence of an upper sealed smoke and fire barrier.
.15 Yearly Retests
All enclosures must be re-tested yearly if any doubt exists as to whether the room has had
any more holes put in it in the last year.
.16 Commonly Needed Inert Gas Clarifications
Inert gases are all heavier than air (with the exception of Nitrogen) and will, according to NFPA 2001, run out of room leaks.
They are not as heavy as halocarbons and usually only run out at half the rate. They do run out though.
Inert agent enclosures have a very narrow window where they must be tight enough to hold the agent but loose enough to vent peak discharge pressures. All inert clean agents need relief vent areas according to their manufacturers. Inert agents still must pass the door-fan tests. If the enclosure has a vent, its area can be checked with the door fan and some vents can be tested for their ability to open under pressure.
.17 Enclosure Integrity Test Verification Form
Because there are so many aspects for the witness to keep track of during the enclosure integrity test, Retrotec has developed an easy-to-follow check-off sheet. You can also find this form in the appendices at the end of this document.
Please feel free to copy this form and customize it for your own organization as you require.