Soundproofing to reduce pump noise

[zephans]

I have a Waterco 2HP (max rated) pump that came with my 12'x24'x54" AG Pool. The pump is oversized (as is typical of AG pool bundles per my reading in TFP and PF) and has a noisy hum during normal operation. The best solution would be to get a dual speed or Pentair Whisperflo pump, but my piggy bank and priorities favor electrical upgrades and deck before replacing the pump.

I found one related TFP thread with keyword "soundproofing" but it didn't have good description of appropriate materials such as MLV (Mass Loaded Vinyl). After spending an hour or so searching TFP and various web searches I think I found a decent solution at http://www.soundproofing.org/infopages/generator.htm:

We've upgraded the basic generator soundproofing info from the book: "Quieting: a practical guide to noise control". The new system is shown below. It is based on the fact that air will go around corners well, whereas sound doesn't like to. This baffling method works well for pool pumps and many other kinds of noise sources.

Enclosure is best made of panels of "Soundboard" or "Homasote" (from the hardwood store), with corner support strips of wood (not shown). screwed, (not just nailed) and glued for strength. Plywood is not recommended because wood transmits sound so readily. "MDF" Medium Density Fiberboard is best. A lined, triple wall box as shown is the most effective, but sometimes a double box may work well enough, depending on the level of sound control needed.

For maximum effect, use the 2" thick "Super Soundproofing Mat" for lining your box. Make sure the box is entirely covered: no gaps. Cement edges for a tight fit. If in a damp environment, use our contact cement as it has a mildew resistant retardant in it. See the "Prices" page for ordering and price info. (On the sidebar). Cut strips of mat for the airtight seal for the bottom edge.
Leave about an inch between the inner and outer boxes for air circulation.

Lead or mass loaded vinyl can be attached over the box for even more sound control. Edges must be sealed! Use lead tape and the non-hardening acoustical caulk available on our prices page.

...

There is additional good info on this http://www.soundproofing.org page so check it out if you need all the details. (I'm all for quoting then linking to original source resources.) Please reply with your thoughts and especially if you have experience (success or failures) deadening sound from an existing pump.

Gratuitous related keywords (for those like myself who search before posting ): reducing noise of, sound reduction of, sound pump noise, sound proof, soundproof, sound proofing.

 

[Pool Clown]

My only worry is the fresh air that the motor would need or, not get. Is this diagram for a generator(temp use)? Keep in mind that generators may not run every day(power outages only?) where as pool pumps run everyday. You could make the outer boxes a little bigger for more air flow. If i were doing this, I would get one of those wireless temp sensors and stick it to the inside of one of the boxes and monitor the temps. But first, Set the remote under the pump motor before you make any encloser first to get some sort of baseline temp so you can see how much the temp rises when in the box. Also, the foam would concern me as well because the foam will act as insulation to keep the heat in. Sorry to discourage...

 

[HarryH3]

Quite often, just doing something as simple as putting a solid barrier between the pump and the bedroom will reduce the noise enough that you won't hear it any more. Just a short wall of some sort, close to the pump will reflect most of the noise the other way.

 

[zephans]

I found putting weight on the top of the motor reduces some noise (by reducing ability to vibrate). My plan is to buy some MLV (Mass Loaded Vinyl) and some stiff wire. I'll construct a set of half- cylinder "hangers" with one open end using stiff wire as my framing, then drape MLV over the hangers. My idea is that free form wire frame construction will better match the round motor and piping challenges than building boxes.

I definitely want to make sure there is sufficient air flow and ventilation, so I'll make sure there is two fresh air ports located near motor ventilation intake. I may make a right turn out of MLV to muffle noise from these inlets. I also need to make sure the MLV (or whatever material I end up using) will withstand high temperatures (to avoid burning up everything).

Project will likely happen next spring. Too many other projects in progress right now to worry about noise. Perhaps I should just invest in ear plugs and call it done until I can buy a lower HP/noise motor .

 

[polyvue]

My idea is that free form wire frame construction will better match the round motor and piping challenges than building boxes.

A true DIY solution!

In California, lot sizes in urban/suburban areas are often too small for a pool, nevermind a pool & spa, landscaping, deck and a 10 x 6 ft equipment pad... The filter/pump pad for my pool was relocated in the planning stage from the back fence/property line to my sideyard, poured to meet the foundation and adjacent to the kitchen wall (this, to address one neighbor's criticism that the pumps would be too close to their kitchen.) Though hours of operation are not excessive, confined to day-time except for the occasional night swim, the noise generated by the main pump and booster is quite noticeable - not just in the kitchen, but in living/family rooms as well. Worse, I've noticed that neighbors I've been close to for years and really like, an elderly couple, whose patio is perhaps 10 or 12 feet distant from the pad, have stopped using it for al fresco dining. Pretty sure I know why.

Building an enclosure to isolate the pumps in my situation would be challenging to say the least. I have three pumps to contend with, all set close to each other and entangled in a spider's nest of 2" plumbing, sensor leads, electrical cabling and control units. I've long thought that installing some sort of sound-absorbant material on the redwood fence that separates me from the "good" neighbors coupled with sound panels attached to exterior kitchen wall (inches away from the pumps) might help reduce the dB. Also, a low sound wall perpendicular to wall/fence at the end of the pad, to deflect noise directed toward the pool and deck back down the length of the side yard.

Most promising solutions turn out to be illusory in that the absorbent material such as acoustic panels and strips are not designed for outdoor use. Your post motivated me to dig a bit deeper and I have found a couple of web sites of interest.

http://www.soundproofingamerica.com/ contains some interesting material, including this article: Soundproofing Pool Pumps And Filter Motors. I think I may have finally stumbled upon an acoustical tile product that can be used outdoors. (See Silent Panel PDF format)

Another web site to explore is Acoustical Surfaces, starting with 4 Ways To Quiet a Noisy Machine

Many thanks, zephans, for starting this thread. :-D

Greg

 

[zephans]

Thanks for posting the additional reference links Greg. It sounds like your lot size constraint is tighter than my 1/4 acre corner lot . I like the idea of using a computer fan to provide positive ventillation (as mentioned on soundproofingamerica.com link). I might also use the flexible ducting idea. I'll post an update when I get around to this project. In the mean time I'd like to see a few people who have tried tackling pump noise post their experience (good or bad) so everyone can learn how well your designs worked or didn't work.

Don't be shy! You learn from success... but everyone learns much more from failure! Just ask Thomas Edison.

 

[teapot]

An interesting idea I came accross the other day, using a submerged pump rather than the usual surface mounted.

Several good points:

The pump is almost silent as it is underwater.
You use a lot less electricity for the same flow rate with a submerged pump.
No overheating problems.
No winter draining down (pump mounted below freezing depth)

 

[Pool Clown]

I'm not sure submerged pumps are continuous duty rated, The affordable ones that is, I may be wrong.

For a possible fix that wouldn't take long at all, is a rubber mat under the pump to help w/ vibration, (1/8 to 3/8 in thickness). Maybe shoving the rubber mat under would shim the pump just enough to tighten up the vibrations (like when you put pressure on the motor)

 

[flintstone]

One source for an appropriate material designed for motor soundproofing is the boating industry. A google check using "marine soundproofing" showed a couple of promising sites offering materials that seem perfect for pool equipment pad applications. One such, http://www.marinefoam.com/engine-soundproofing.html?page_type=engine-soundproofing even has material you use under your pump to dampen vibration. Designing an appropriate structure to allow access to the filter for disassembly and cleaning and to provide clearance for the heater is my current sticking point.

 

[spishex]

As poolclown and flintstone mentioned, a rubber mat goes a long way. If you're getting any noise from vibration you need to isolate that first rather than trying to block the noise that's being generated. Drain mats work very well for that.