Experience with ISI's freezing up in winter, or not?

[enginegirl1]

Both my township and work fire departments are looking at buying new packs according to the new NFPA 2007 guidelines. The township uses old ISI's, which we love because of the easy on/off air.

I did a search on this site for pack comparisons and read all the entries, which were very helpful. I saw some references to ISI's sometimes freezing up in the winter. It is so hot today in Ohio that I can't imagine anything freezing up ever again, but I suppose one day it could happen.

Looking for strong evidence here. Did your ISI's freeze up or not? Why do they do this? Or was this just a couple of isolated cases?

Thanks in advance for your help.

Best wishes,
Amy

[Firetacoma1]

Ours never froze up but the air switches on the masks would get to the point where they were inoperable. This along with no dealer support in our area led us to switch to MSA. Couldn't be happier with MSA.

[Bones42]

Old ISI pack, with a whistle as the low air indicator. Water got in the whistle and froze. No low air alarm.

I believe they have changed the design a little since then, but we have not used them since late 80's.

[enginegirl1]

FireTacoma and Bones, thanks for the replies. We too have a couple of sticky airswitches, which is not fun when going interior. However, our packs are old so I'm hoping the new stuff is improved. Also, we too have the whistle low air alarm and I'm betting the NFPA 2007 version will be different, for volume if nothing else. Haven't seen that demo'd yet. Thanks - will keep both of these things in mind when looking at their new prototype airpacks.
Amy

[kprsn1]

We've been using ISI for years and I don't recall any reports of them freezing up. The switches still need a little work. The old models where you put the regulator in sideways and turned would occasionally jam up the little red switch and it would break off. On our new models with the up down switch, I've had one side of the clip break off. It still worked but had to repaired as soon as I was back at the station.

[enginegirl1]

Kprsn1, thanks, that's good to hear. I would like to think that maintenance will keep us in good shape with the switches. To me, the easy on/off air is a huge advantage of the ISI.

We had the Scott rep in at work the other day and he made the comment that only Scott has a non-piloted airflow mechanism, and this gives them superior performance against freezing in the winter. This would imply that all the other manufacturers are seeing this freezing problem. I'd like to hear from others about winter regulator performance before we buy.

Thanks again,
Amy

[onehotcowboy]

Im not familiar with the ISI'S, but we use SCOTT. The temp gets down to 30 below zero here without the wind chill in the winters. The only time we have had problems with the regulator is when you come off air, in that extreme temp and dont tuck your regulator in your coat, all the moisture from breathing can freeze up your regulator. NEVER had a problem other than that, but at 30 below, nothing works well,even our engines freeze up on occasion, water freezes almost instantly, have a inch of ice on water in drop tank within minutes. So is it flawless when its cold, no, but little tricks of the trade like putting it in your coat will help with that.

[HotTrotter]

We have been using ISI for years. We upgraded to the latest model 3 or 4 years ago. We have never had a pack freeze up. And we get to work in sub zero temps all the time. I love the ISI packs, I have been able to get a 45 minute bottle to last over 2.5 hours by simply turning the air on and off as needed. I also like the fact that they have a bigger field of view than any of the other packs. We evaluated all of the packs and went with the best, not the most popular.

[TNFF319]

IF you are getting new packs look at msa. We just got a whole new set of MSA's, and I love em. The are way lighter than the scott's we used.

[mcaldwell]

We used to have problems with our older Draegars freezing up on occasion, but after some training, and turning the annual maintenance over to the authorized service center the problem went away.

We figured we were not drying the parts thoroughly enough after cleaning, and we didn't clean the grease and oil out of the mechanisms well enough during the annual services (inhouse in our poor days). I also suspect our air supply was not as dry as it could be. Even though it was not enough to notice, it seemed enough to mess up the units in the heart of our Canadian deep freezes.

[HotTrotter]

IF you are getting new packs look at msa. We just got a whole new set of MSA's, and I love em. The are way lighter than the scott's we used.

All of the new packs weigh about the same give or take a pound. Where the biggest difference comes in is how they fit the back frame to the body. Some packs will carry better than others. I also found that some were constructed much better, and were easier to use. Also when I looked at packs I evaluated how much stuff was hanging off or would act like a hook or catch debris. I also looked at ease of maintenance. The ISI was nice in that respect in that the only use 8 AA batteries, nothing special and all the same. But from a purely functional level, they all do the same job.

However, as with everything in life, there are pros and cons to everything as well as trade offs. Nothing is perfect.