Silent Accelerated Test Method – Safety Risks

Aaron Lee, C.E.T., GIFireE Team Lead, Fire Protection Engineering, AtkinsRéalis

Disclaimer: This article is intended to promote safety awareness to technicians, building occupants and building owner/operators. Safe work practice, safety training and employee safety is the responsibility of company health and safety policies, including the adherence to provincial health and safety legislation.

The 2019 Editions of CAN/ULC-S537, “Standard for Verification of Fire Alarm Systems” and CAN/ULC-S536, “Standard for Inspection and Testing of Fire Alarm Systems”, identify three methods to test batteries:

  • The 24 hour standby plus full system load,
  • the manufacturer’s recommended method, and
  • the “new” silent accelerated test method.

The new silent accelerated test isn’t exactly “new”. Prior to the 2019 editions of the noted standards, specific guidance was provided on how to perform and calculate two (2) load resistor test methods; the “silent” test method and the “silent accelerated” test method. Using a formula, test timing was prorated (reduced) by using electrical inputs and then multiplying by an accelerated figure. It was noted in the appendix of previous editions of the standards that the silent accelerated test method is based on a 5-minute alarm (bell) requirement, originally intended for smaller systems.

For larger systems, the silent test was recommended to be followed, which still required the 24 hour plus full load testing time period (if not conducting live audible system load testing). The 5-minute test was originally provided to address the battery load testing of systems as outlined in the National Building Code of Canada, Division B, Subclause 3.2.7.8.(3)(iv) “Emergency Power for Fire Alarm Systems”. The guidance on what to do for larger systems (old silent test) has since been removed, such that, in the 2019 standards the silent accelerated test appears to be a solution that can be applied to any size fire alarm system, large or small.

Further to this, the use of battery capacity meters is not permitted as a testing solution. Since 2013, the normative portion of the standard states explicitly, “NOTE: Battery capacity meter test is not among the accepted methods for performing the battery tests”. Some industry stakeholders may argue that a battery manufacturer’s method may allow the use of a battery capacity meter thus creating a loophole in the standard. However, this approach to the requirement could be contentious as it contradicts the standard’s explicit note. With the battery capacity meter method considered as unacceptable, and with limited explanatory information on various method options, the new silent accelerated test becomes a more attractive solution. However, the new silent accelerated test method presents more safety risks (when compared with the other test options) to fire alarm technicians, building occupants, and building owners who will be using this method more commonly to meet regulatory compliance. This is especially true for smaller buildings where during an annual inspection, a 24-hour standby load plus full load test is not an affordable test option, making the silent accelerated test a much more common occurrence.

So what’s the quick fix? Code revisions with new options? What are acceptable battery manufacturer’s approved methods? If there were revisions to the standards for new options, it may take years for it to be made law. This article is not provided to detract from the silent accelerated test method, but to promote discussion and spread awareness of the risks involved when conducting the test. Simply speaking – safety.

The Canadian Labour Code and Provincial Occupational Health and Safety Acts/Regulations across Canada require that employees are trained and qualified to conduct their work tasks. However, assuming that this test method could be more actively utilized within industry as it becomes more common, various safety risks should be contemplated as they may not be specifically outlined in current industry literature for this type of work.

It very important to note, that prior to any work on fire alarm systems, training on work procedures and proper testing equipment shall be provided by the employer prior to completion of work tasks. If silent accelerated testing is performed, proper training on this method, provision of the appropriate testing equipment, and personal protective equipment and clothing shall be provided.

The following is a list of risks and hazards that should be considered, but not limited to, when conducting the silent accelerated test:

1. Burns

The test uses a load resistor connected to batteries for a duration of five minutes. During this time the load resistor becomes extremely hot. It is recommended that proper personal protective equipment and clothing (PPE&C) is used to limit exposure to burns during the test (including but not limited to gloves and long sleeves). Further to this, the explanatory portion of the standard discusses an alternate option with suitably sized resistors based on manufacturer’s capacity charts. Use of adequately sized power resistors would reduce risk of burns. This would be especially important with larger batteries. As such, while considering the allowance in the standard, a larger wattage power resistor (such as 500 Watts) would reduce the amount of heat generated.

2. Sparking

Connecting batteries to the load resistor has the potential for sparking. It should be noted that sparking is substantially different with DC voltage than AC voltage, and the risks are much less. However, while the risk is low, it should be considered. The larger the battery, the higher the potential risk of injury should a sparking incident occur. Loose terminals, accidental shorts across terminals, and corroded terminals will cause sparking. It is recommended that all terminations and wires are securely attached, kept in good repair, and all terminals need to be clean and clear of corrosion. Best practice is to connect the negative terminals first. It is also recommended that the appropriate PPE are used to limit risk (including but not limited to safety glasses).

3. Fire

A fire hazard is possible with the amount of heat generated by the test or from sparking. The load test is conducted over a period of five minutes. With the potential of this test becoming a routine task during a technician’s workday, it is possible that technicians may become distracted by other tasks or activities. Incorrectly sized wires and loose terminations can also cause fire or equipment failures. The test should be conducted with the technician’s undivided attention for the entire duration of the test. It is recommended that the test be conducted in controlled environment, away from the general public, combustible materials and finishes. As noted above, the use of a higher rated power resistor would reduce the amount of heat generated, limiting the chance of fire.

4. Battery depletion

After a load test, batteries will be depleted. If the battery test is accidentally left unattended for period longer than 5 mins, batteries could fully deplete. Larger batteries can take longer to charge depending on the charging current. Some batteries can take several days to return to a full charge after a total depletion. Various calculations can be completed to determine recharge times based on battery size, charging current and the battery state of charge. Below is an example of a charge time formula.

*Rough Estimate battery charge time formula:

Charge Time (hrs) = [battery capacity (Ah) /charge current (Ah)] x state of charge %

*It should be noted that relative to the age and temperature of the battery, that the state of charge estimate, and charge time value could vary. The above formula should be used as rough estimate and is not intended to be exact.

Technicians should illustrate to building owners the system condition after this test, estimated time to full charge, and what battery depletion risks are. Building owners also need to be notified that the fire alarm system may be at risk if a brown out occurs following a silent accelerated test before fully charged (ie. non-functional or a degraded standby/full load time period until full charge). Alternative measures as identified in the building fire safety plan may be required if the fire alarm system is not functional due to lack of secondary power during an outage.

5. Battery/Equipment Damage

The battery should be placed a safe distance from the resistor. The heat generated from the resistor has the potential to damage the battery or other equipment if placed too close to the resistor. This risk is also reduced through use of a higher rated power resistor.

6. Large Batteries

Larger batteries increase all the risks noted above. It is assumed that larger fire alarm systems typically utilize batteries larger than 13 Ah. For batteries larger than 13 Ah, the 24 hour plus full load test, or the manufacturer’s recommended test method should be considered instead of the silent accelerated test method to limit the risks.

As previously stated, this article is intended to promote safety awareness, spark discussion, and engage the fire alarm community to keep our technicians, our buildings, and their occupants safe. No matter how you feel about the subject, it’s important to talk about it. As fire alarm technicians we keep others safe by maintaining fire and life safety systems for buildings across our nation, but let’s keep ourselves safe too. Safety is no accident.

Aaron Lee is the Fire Protection Engineering Manager with AtkinsRéalis. He is a Certified Engineering Technologist, registered CFAA technician (20+ years), a ULC Technical Committee Member, and the Technical Committee Chair of the CAN/ULC-S1001 Standard. For more information, he can be reached at Aaron.Lee4@AtkinsRéalis.com.

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