Use of seawater for fire suppression

[RickH]

Hello, I am a brand new registrant to the FireHouse forum. Was a fire officer in Colorado, but moved onto my sailboat in 2004 and sailed away. I am now on the Western Pacific Micronesian island of Pohnpei. Newly hired as "Emergency Services Unit Administrator" for the next two years to improve EMS/Fire/Rescue/HazMat/MCI.
My question is regarding use of seawater in firepumps. I have no experience with this issue coming from Colorado. Can I get some input from those of you with experience pumping seawater and the care/maintenance concerns for the apparatus/pumps?

[chiefengineer11]

Hello, I am a brand new registrant to the FireHouse forum. Was a fire officer in Colorado, but moved onto my sailboat in 2004 and sailed away. I am now on the Western Pacific Micronesian island of Pohnpei. Newly hired as "Emergency Services Unit Administrator" for the next two years to improve EMS/Fire/Rescue/HazMat/MCI.
My question is regarding use of seawater in firepumps. I have no experience with this issue coming from Colorado. Can I get some input from those of you with experience pumping seawater and the care/maintenance concerns for the apparatus/pumps?

Navy (and Coast Guard) ships use seawater for firefighting and many other uses. The pumps that I remember from my Navy days ('59 - '63) were all bronze. Most of them never saw fresh water. Some other pumps, such as portables, also pumped sea water but were flushed with fresh water after each use, when possible.

I remember being in Hahn's factory in Hamburg, Pa. when our '68 Hahn was being built. There was another engine being built at the same time, for West Palm Beach, Fla. It had an all bronze pump. I was told that they spec'd bronze because they frequently pumped salt water. I presume that they also flushed the pump after using salt water. I don't know if they still spec bronze pumps or not. I'm sure that there are others that do, too.

[FIREMECH1]

Actually the make up and build materials for "true" salt water pumps have a chemical composition of nickel, aluminum, and bronze. As far as I remember, this was the best to defeat the corrosion of salt water.

Not knowing what RickH has for pumps, I would assume they are still cast iron, unless built with the "bronze" material.

Either way, if you pump seawater, take the time after operations to flow some fresh water through the whole system and all the discharges. This should lengthen the life of the whole system from problems and corrosion.

FM1

[StuRat]

We were told you can use seawater, but to make sure everything is flushed after with fresh water. We were also told about a pump that was used for salt water, that wasn't flushed. They ended up blowing a 20cent size hole in the side of the pump 2-3 months down the track.

[nmfire]

Up in my old neck of the woods last week, there was a large residential structure fire at huge McMansion on the water. The city water system in this small town was overtaxed in about five minutes so they have two or three trucks drafting out of the ocean. I'm sure the engineers cringed, but as long as you flushed it out and follow the manufacturers recomendations, I'm sure it will be fine.

[fire49]

http://www.firehouse.com/topics/stra...n-water-system


Wonder what the fire boat pumps are made of????

[fire49]

Call pump maker for recommend practices

[Bones42]

Well, we've been using sea water for about 75 years. After operations, we flush with "fresh" water. Haven't had a pump issue yet.

[chiefengineer11]

Well, we've been using sea water for about 75 years. After operations, we flush with "fresh" water. Haven't had a pump issue yet.

If anyone would know, you'd be it.

[RickH]

Thank you for the feedback, it sounds like doing a freshwater flush is the main thing, luckily it rains tons here. I'll do a specific check with the pump manufacturer to double check, but it sounds like there is not issues with seals, etc. as long as the flush is done religiously.

[Johngagemn]

If you are going to be pumping seawater on a regular basis you will want to use a bronze pump with a monel shaft. Most bronze pumps also use seals with different materials designed to withstand harsher water conditions. This is the type of pump that is used in saltwater fire boats. Most major pump manufacturers offer some, if not most, of their pumps in bronze. Waterous offers many bronze models including CM and CS midships.

An iron pump will tolerate occasional seawater usage as long as it is thoroughly flushed with clean water afterward. Keep in mind that in order to flush it properly you must also flush the tank and ALL intake and discharge piping if you want to keep things from corroding away.

[islandfire03]

Just saw this thread:
Being on Islands surrounded by the briny deep we used to have an engine with bronze pump and manifolds with bronze valves. It has been retired now.

Most of the problems with pumping seawater is going to occur in the newer delrin or other synthetic "Ball" valves in use today. They and the combo nozzles really catch heck from all the smaller grit and contaminates found floating in the ocean. Flushing the plumbing thoroughly will keep the damage down but not eliminate it completely. Make sure to check the anodes and keep a set of spares as seawater will speed the consumption of them.

[npfd801]

Doesn't Hale make a stainless pump? Not saying that's the answer, but it is out there...

[Fire304]

Wonder what the fire boat pumps are made of????

Actually most "modern" ones are just cast iron, but they are protected by sacrificial anodes (zincs). Back in the day they they were special bronze construction, but that's just too expensive for most people these days.

One other food for thought, all them dissolved solids in salt water can prevent your foam from sudsing up, make sure if you use foam it is salt water compatible.

[txgp17]

Doesn't Hale make a stainless pump? Not saying that's the answer, but it is out there.

Actually, they'll make any cast iron pump they offer in bronze, but you have to order at least two if I recall correctly.

EDIT TO ADD: Hale Product Application Guide, page 29.

Pumps available as single unit order in bronze:
QSMG
QG
CBP
AP (APS)
PSD
RSD
DSD
CSD
8FG
RMB
RMC
RME
All multiple order pump models are available in bronze as a special order

For the record, I've never operated a pump with salt water, but I have operated a few boats in it.

Salt water is nasty stuff. It will corrode almost anything and everything; it's just a matter of time. But, getting salt water on things usually doesn't hurt them. It's leaving salt water on or in them that ruins them.

If you adopt a meticulous practice of completely flushing the entire pumping system after using salt water, I doubt you will have any problems.

Also, the US Navy has used cathodic protection on their ships for decades. While this technique isn't effective on automobiles (they're not grounded, because of rubber tires), you could employ such a system while you're pumping the sea water. Hale already offers sacrificial anodes. By applying the proper electrical charge to them, they become even more effective.