Testing/Commissioning of a Foam Fire Protection system

[jksman]

Just wondering what are some possible ways we can go about testing our foam fire protection system without filling the entire building with foam. Or is this the only way?

 

[NightME]

It's one of the only ways you can do it correctly.

If you measure the flow at each generator you can extrapolate the consumption rate of foam concentrate and validate the duration and flow.

 

[LCREP]

How was it tested when it was installed and accepted?

If it is a low expansion say 3-6% foam system install piping after the foam inductor to a test header. Flow water via the test header at the required GPM when reached turn on the foam and take sample to determine the % of foam. Check with your environment agency some will require you to collect the foam, others will permit it to be discharged to a drain and or seep into the ground.

 

[Sdpaddler50]

Acceptance, and subsequent testing after that is one of the main problems with aqueous foam systems. Most system are therefore not tested properly. A relatively new system is out that uses air - air/compressed foam = ACAF for example. I am not sure if it will work for your application, but if you google it, you can find more.

 

[jksman]

Thanks guys.. Looking into a few details with it now.
It is not currently installed yet, the building is still under construction.
One of the ideas we have thrown around (still haven't done the research yet) is once line is finished, to first test out the sprinkler system with water to verify flow and ensure they are the same within acceptance.
We could then test one sprinkler with foam to determine the coverage and it's spray pattern and then hoard the other ones to prevent the entire building from filling.
The idea of a test header also sounds ideal.

 

[stookeyfpe]

Low, medium or high expansion foam? What's driving the requirement for the foam-H2O system? I ask because I had a designer recently tell me that for a new private aircraft hanger that high-expansion foam was required and after researching the 2012 IFC and NFPA 40-something I figured out sprinklers were an option.

 

[jksman]

Both high and low expansion foam. It's a chemical building with various tanks settlers and mixers.
high expansion will be used for ground floor and operations where low is for any trenches and inside the tanks.

 

[Sdpaddler50]

I will let you figure out what is best for your project, but you may want to look at compressed air foam. You wont have the discharge test issues you are concerned with. I am definitely not a subject matter on foam, but I did some prelim research about 6 months ago on it and wrote an initial design spec for a foam system. It is <FM> approved, and can be used for flammable liquids. The project we had involved very low fp liquids in plastic containers, so we had to have foam, since water alone would not cut it. But, the project was cancelled early on so it did not go through.

 

[stookeyfpe]

Without doing more research I would be hesitant on CAFS for flammable liquids. I suspect with CAFS your foam quantities are reduced due to a lower concentration. However, the higher concentration one is required to have using a conventional AFFF or AFFF-ATC provides higher surface shear which increases the breakthrough times. This issue as extensively studied several years ago by an API task group.

I know nothing about your process chemistry or unit operations to make any conclusive statements. However, I am concerned about mixing a High-expansion foam system with a low-expansion foam system. The design approach and equipment requirements are different and I'm not sure how these two methods would work under a fire condition. I also have concerns if this equipment is all in one building or area where the unit process is combined together. I wouldn't want to be an operator trying to wade through high-expansion foam while moving through a process area.

With this process being indoors your unit processes may be a candidate for using optical flame detection and motor operated valves to isolate process feedstock and finished product piping when a fire signature is detected. This combined with conventional sprinkler protection for controlling the fire and cooling process equipment may offer higher reliability and lower ITM costs.

 

[Sdpaddler50]

Stookey,, as noted, I am not a foam expert but did some prelim research about this in the past. The research folks at FM who do know foam very well have approved CAF for low flash point flammable liquids. Their testing processes are very thorough and methodical and often more restrictive than other codes and agencies.