Some discussion from RCAAM concerning wet vs dry pipe sprinklers:
Dear All,
This very interesting and enlightening conversation (below) debating the benefits of wet pipe vs. dry pipe fire suppression systems traveled the list last summer. I saved it because we are about to build a new addition and sprinklers are in the plans.
In the earlier e-mail exchange, wet pipes were the preferred option, but I think they were primarily discussed in terms of collections storage areas. Our new addition will have both both collections storage and gallery areas. Someone here has suggested that we go with a wet system in the storage spaces and a dry system in the galleries. The reasoning given is that lenders may require/prefer a dry system where their works will be shown. I have never personally encountered such a request and have reservations about installing the dry and/or a mixed system approach in the new building.
Does anyone have an opinion on this? Have you encountered such requests or do you request dry over wet pipes in the display areas of organizations you lend to? Has anyone raised the issue with you before?
Your thoughts on this (as soon as you can send them) would be very much appreciated!
Frances
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Frances Lloyd-Baynes
Collections Registrar
American Swedish Institute
Forwarded conversation
Subject: [RCAAM] wet pipe versus pre-action dry pipe
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From: Warren Woods <warrenw@hnoc.org>
Date: Tue, Aug 24, 2010 at 9:36 AM
To: RCAAM@si-listserv.si.edu
Greetings from New Orleans.
I have been hearing and reading conflicting reports on the current museum standard for sprinkler systems, especially wet pipe versus pre-action dry pipe.
Can anyone shed some light on this topic for me?
Thanks as always,
Warren
Warren J. WoodsCollections Manager/Exhibitions CoordinatorThe Historic New Orleans Collection533 ----------
From: Bruce MacLeish <bruce@newportrestoration.org>
Date: Tue, Aug 24, 2010 at 11:02 AM
To: RCAAM@si-listserv.si.edu
Hello Warren,
First of all, let me say that I loved visiting your museum a few years ago, and I look forward to getting back there someday.
As for your question, I can’t say that I have all the answers, and perhaps some other sources could be of use to you, such as the NFPA, the National Park Service, and the AAM’s Museum Association Security Committee. For starters, I checked my binder of material from the Canadian Conservation Institute, and I can quickly quote their recommendations: “The cost of automatic sprinkler systems can be kept low by selecting conventional wet-pipe systems; on/off sprinklers, pre-action systems, and cycling systems are more expensive to install and maintain, and do not necessarily provide better protection. Many of these special systems are plagued with maintenance problems and are hardly ever required in museums.” So, there you are. However, that information was published about ten years ago, so it may not indeed be the last (i.e., latest) word on the subject. It’s a start. Note that neither CCI, nor I, will address water-mist or chemical systems.
In my own experience, I can relate life with both wet-pipe and pre-action dry-pipe in one of our larger buildings. Fortunately, we do not have empirical data about how well our systems would extinguish a fire, but I think that the historical information proves the value of sprinklers. Our wet-pipe system has been simple to maintain and has not given us any problems in the ten years it has been active. We do have areas of dry-pipe service, originally installed because of a perceived risk of freezing in certain areas. If anyone had bothered to check, it would have been evident that the freezing risk is virtually non-existent, and that would have spared us a good deal of trouble and expense. The dry system involves an air compressor to keep the pipes under pressure, to help hold back the water, until the system is activated. This has happened several times, through faults in the system, and not because of fire. Fortunately, the sprinkler heads kept the water from soaking the museum areas when there is no fire; still, a service call is required, to empty the water from the dry system and be sure everything is once again in readiness. Of course, each incident also involved an automatic alarm that brought the fire department to the building.
To improve performance of the system, we encouraged our service people to raise the air pressure in the pipes (after two false activations in two weeks); although they seemed unsure about the efficacy of that step, it has worked well for the past couple of years. We also installed a secondary alarm to ensure that the air compressor for the system is working properly. The alarm sounds every time the system reaches its low-pressure limit (about once each week) and shuts off when the high-pressure limit is reached. Our security crew, after being scared witless by the loud bell, check to see that the compressor is running as it should. They note on a log sheet the air pressure at various times of day, and the compressor cycling. I should also add that when the system is activated, whether by accident or for a test, the dry pipes have to be drained, and some of the drainage points are behind exhibit walls, and in other areas where the disposal of many gallons of water is a pain in the neck. Notice how none of this information involves the wet-pipe system? As I learned from a colleague at an AAM session, bits of moisture left in a dry pipe can eventually rust through the pipe walls, leading to failure and likely flooding. I suppose no system is perfect, but the dry-pipe system seems much less perfect than the wet-pipe.
I can only add that having the system tested is very important. You do not want to be the careless fellow who neglected something like this. We discovered that for some reason our service company did not have us on their list after the system was installed, but fortunately there were no serious repercussions. Eventually, the service company let us know that even though a flow test (blowing large amounts of water through the valves and pumps, and producing a large hole in the ground, if you’re not careful) was not required, it seemed like a good idea. Otherwise, you can’t be sure that the all-important pump even works. Well, of course. I can only hope that we have reduced our ignorance to a more reasonable level through these experiences, which I am willing to share with colleagues, so that you may escape some of the less-desirable consequences.
Comments are welcome, and thanks to others for your help in the past.
Bruce
A. Bruce MacLeish
Director of Collections
Newport Restoration Foundation
Please let me know when you visit New Orleans again and I need to get up to Newport. It is on my list.
Thanks again,
From: Bruce MacLeish [mailto:bruce@newportrestoration.org]
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From: Melissa deBie <melissa.debie@gmail.com>
Date: Tue, Aug 24, 2010 at 12:43 PM
To: RCAAM@si-listserv.si.edu
I did a lot of research into dry vs. wet a couple years ago. I have to say that wet pipe won because of the personal experiences as well as stories about other dry pipe systems.
I was in a building that was about 10 years old with dry pipe. 10 years was about the expected lifespan for the dry pipes because after that we had to continually replace pipes all over the building. Even though they're supposed to be 'dry' pipe, they run water through when the system is tested. No matter how good the system is, there's going to be a little water left somewhere. A little water in a mostly dry pipe system=corrosion. The pipes were basically rusting out from the inside. (We also noticed that once the pipes were done we started getting leaks at the joins. They weren't just water leaks, they were brown/black gunk leaks from the extra buildup inside. Dry doesn't always equal empty either.)
Go with wet pipe. In the end it'll be a lot cheaper and less overall maintenance.
We also have a dry pipe system and it does require a lot of maintenance for the compressor and the pipes that get flooded and drained and thus have to have rusted sections replaced periodically. In the end whenever there is a drop in pressure, the pipes flood. If there was a hole in the piper, water would come out at this point. So having a dry pipe system doesn’t prevent water problems and may actually increase the likelihood of leaks.
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