(In Response to "My Other Hat," Oct. 30, 2003, Command Post, and subsequent post by Rodger Ricciuti, "About Using Foam at High Rise Fires.")

Great questions from Rodger. I will give them my best shot.
For high-rise applications, Class A foam and CAFS are the way to go. One of the obvious benefits is significantly reduced water damage. I had the unfortunate experience of being in a hotel fire several years back. The fire started on the roof and was confined to a relatively small area there and on the top floor. My room was on the first floor, not the lower level, and I had about 4 inches of water in my room. All told, there was over $1.5 million in water damage to that wing of the hotel. With Class A foam or CAFS, the damage would have been a fraction of that amount.

Another benefit when using CAFS is the reduced weight of the water column in standpipes, making it easier to pump to higher levels.

On sprinkler heads, you do not want to go too dry (rich) with the foam. The rising heat column from the fire can "blow" the drier foam off to the side and the foam solution will not get to the seat of the fire. It is better to error on the wet or lean side. You do need a good proportioner that will maintain its accuracy over a relatively broad operating range, so if one head goes off, or 12 heads go off, it maintains a constant proportioning rate. The electronic direct injection proportioners that are widely in use today, are more than capable of giving the required accuracy in these situations.

I cannot address the effect of foam solution on seals and fittings in sprinkler systems. Corrosion should not be a problem. We use Buna N seals in our pumps without any problems. I am not aware what type of material is used in the sprinkler head o-rings.

On the post-incident effects, yes you do need to be concerned about contaminating the municipal water supply. Having said that, I am not aware of anyone who has gotten seriously sick or even died as a result of digesting several ppm of soap solution from the municipal water supply. The question that has to be asked in doing a benefit/risk assessment, does the improved firefighter safety and reduced property damage outweigh someone possibly coming down with a bad case of diarrhea? That is a call the IC would have to make and live with.

Hopes this helps.

Bill Ballantyne
Hypro