Attic Fire Lessons Learned

[Admin]

I thought I would pass along some information that may be helpful following a small fire that our campus experienced on February 2 when an HVAC hydraulic motor-operated actuator for a hot water reheat coil in a confined attic seized, overheated, and started a smoldering fire. (I have attached photos of the burned actuator and a non-affected one.)

After smoke was noticed by our HVAC technicians who were in the building troubleshooting a heating problem, they pulled the fire alarm. It should be noted that just before smoke was discovered, our staff heard the actuator squealing prior to the 20a circuit breaker tripping in the distribution panel.

Following evacuation of the 65-year-old 37,000 GSF academic building, our local fire department arrived and had a difficult time accessing the origin of the fire/smoke due to a very confined attic with minimal access and a large amount of plumbing, ductwork, insulation, and conduit. After they decided to attack the fire from above, they had to trench-cut the multi-layered roof in multiple locations to extinguish the fire after a significant amount of burning across some attic trusses, supports, and insulation.

There were no injuries and minimal water was used to extinguish the fire with very little damage to the building space. Smoke cleanup, attic damage, and reroofing will be nearly $400K when everything is fully restored.

While we were able to reoccupy most of this building within 24 hours, the section directly underneath the fire remains closed during restoration and reroofing.

We have learned some maintenance lessons from this incident and are sharing them below:

• The affected Siebe hydraulic actuator was at least 15 years old and was not easily accessible in the confined attic space. Although the manufacturer’s manual says there is no maintenance required, we now believe there should be an annual visual inspection to inspect for oil leaks, signs of improper operation, or overheating. We found multiple actuators in this attic that exhibited such signs – included the failed, burned unit, and we are replacing 12 of them.

LESSONS:
o We will implement annual visual inspections of all actuator motors in overheads, attics, and confined spaces.
o We will ensure we have necessary access doors in overheads below attic space that is tight so we can see every actuator.
o Per ASHRAE standards, hydraulic actuators have a max 15 year service life, so we will more closely adhere to a replacement plan
o These actuators were powered by 115V circuits connected to a distribution panel 20A breakers. We will install disconnect switches and fuses at each actuator (the motors draw about 10w/.135a when running) to provide for easier maintenance and for quicker fault isolation in the event a motor fails.

I hope this information is helpful. Please let me know if you have any questions.
Kevin Doyle