Eyewash Station - Water Hammering

Does the problem persist if you close one valve (hot/cold) at a time and then run the eyewash?

Sort of sounds like a mixing valve issue. Too much pressure? Too little?

Yes. The problem exists running hot or cold, and increasing and decreasing water pressure.

OK. Sorry, I should have asked more questions to start. Just a few more.

Assumption 1: There is a paddle at the basin, and operating the paddle starts the waterflow out of two fixed diffusers, spraying water into each eye, catching in the basin. This functions correctly; i.e. no hammer.

Assumption 2: There is a flexible hose attached to the riser somewhere near this paddle actuator. This is a body wash. The other end is a squeeze valve with larger diffuser. When you operate the squeeze valve, it functions improperly... the water hammer issue is evident.

OR, are the two functions swapped? OR, do both hammer all the time?

Whichever is the case, it probably is a bad diverter. Assumption #3: If the paddle is open and the water is running, and then you squeeze the valve, the basin wash shuts off. If assumption #3 is correct, a bad diverter valve is the most likely culprit.

If assumption #3 is incorrect, and it hammers all the time... well, it's broke.

Assumption #1= No. When I push the paddle to start the flow, the chattering or hammering starts.

Assumption #2= No. There is no shower attached.

I am considering adding water hammering arresters on the incoming flow to the eyewash. But what I don't know is if the problem exists around the balancing valve.

Is there a way to test if the problem is at the balancing valve with out replumbing the whole set-up?

Hello Toomany.

I was leaning away from fluid hammer in the pipes, this due to both hot and cold chattering (I guess) equally. A solid test would be eliminating the eyewash valve and running the water. This test will confirm where the problem is.

It still sounds like the diverter valve in the mixer.

Maybe you need to install water hammer arresters on both the hot and cold lines. The small column of air in the arrester acts like a shock absorber, since it will compress while water will not.

You can try one of the big-box hardware stores. Here's one manufacturer's info:

http://www.siouxchief.com/Supply/Arresters-And-Trap-Primers/Water-Hammer-Arresters2/Mini-Rester.7R7YG

The appropriate term for this is most likely not 'water hammer'

Strictly speaking, water hammer DOES NOT occur when water is flowing. It only happens when you suddenly stop water flow. What you have is more likely analogous to 'water chatter' in a household that is usually attributed to a faulty washer in the facet. Have you inspected your paddle valve? Do you have a faulty regulator?

Water hammer can occur when water is flowing. You information is incorrect.

Water hammer can occur any time the flow of water is diverted, or altered as in opening a branch line abruptly, or closing or opening a supply valve. The solution may be the same in either case.

Cheers.

Try reducing the flow rate through your supply pipe.

I had this problem. I fixed it by making a tee fitting on both the hot and cold pipes leading to the eye wash station. (the hot one only went to the overhead shower) From the tee fitting I soldered a short piece of pipe (a couple of hand spans) going straight up, and capped it off. Scraps of pipe are good for that.

It wasn't a water hammer specifically, but some sort of resonant frequency humming in the long pipes, the effect was like a gentle hammering or spluttering during use, and when you closed off the paddle, there was a big hammer like bang.

same easy fix for both problems at once.

Good luck...

I thought you could only use cold water in safety showers and eye wash stations to reduce chemical reactivity? I have been definitely told this while working in the semiconductor industry and in college chemistry labs.

Has this changed?

ANSI/ISEA Z358.1-2009 requires the use of tepid water in eyewash fountains.

Tepid water is defined as 60°F for the lower limit and 100°F as the upper limit.

I am assuming this is the standard in force.

Jim Johnson, chairman of the ISEA Emergency Eyewash and Shower Group and general manager of Encon Safety Product said "By defining a suitable delivery temperature of 60 -100?F, the standard seeks to ensure that the victim continues flushing the affected area to minimize any damage."

I didn't design it, I just installed it man! All this was in an aircraft hangar, inside the space but near the door. I think people were worried about the hydraulic systems, especially those new fangled artificial fancy designer hydraulic fluids they are using on aircraft today.

The hot water never did actually get to the eye wash station, they went to the shower associated with it. I don't think a single user would ever get to the warm water, there must have been 100 feet of three quarter inch copper pipe! But, presumably, if there was a bunch of people cycling through, they would eventually need the mixed hot-cold. To my admittedly fading memory, they didn't bother mixing the hot and cold for the eye wash station itself.

My only real problem (as usual was political) was to get permission to put the curtain around the shower. The Looie seemed to think it was superfluous but finally I found the requirement in the CCOHS for that too. They don't give a lot of reasons for their decisions.

Toomany,

Solution to your problem is provide an Air Chamber by using tee connection cut one foot of pipe and cap it on top portion the other end connected to tee, then the bottom tee connection for your water supply (either hot or cold) front connection of tee is your water feed to eyewash. The Air Chamber will serve to absorb water hammering. There are also a lot of solution in the market but this one is the cheapest.

Um...comment 12....