PAPR Filters

[Mark Jundanian]

Well this was interesting, so thought I'd share. I'd just taken off my Sundstrum PAPR when I noticed fine wood dust falling out of the filter cases. On opening the filter cases I found a good deal of wood flour, both just loose and in the filter pleats. The inside pleats looked perfectly clean.

Now I've been using the same filters since Raleigh so I didn't think it was unreasonable to need to change them, but the unit has an alarm that's supposed to tell you when the filters need replacing. So I decided to look a little further.

First I tested the filter warning system and that is working. Since the dust was getting everywhere I blew the filters off directly into the DC, then I remounted them. Then I tested the airflow with the gizmo Sundstrum includes with the unit and airflow was better than spec.

I don't think blowing the dust off made that much difference. It just appears that a good deal of fine, but still macroscopic dust can collect in there without clogging the filters.

 

[Jim Reynolds]

Well this was interesting, so thought I'd share. I'd just taken off my Sundstrum PAPR when I noticed fine wood dust falling out of the filter cases. On opening the filter cases I found a good deal of wood flour, both just loose and in the filter pleats. The inside pleats looked perfectly clean.

Now I've been using the same filters since Raleigh so I didn't think it was unreasonable to need to change them, but the unit has an alarm that's supposed to tell you when the filters need replacing. So I decided to look a little further.

First I tested the filter warning system and that is working. Since the dust was getting everywhere I blew the filters off directly into the DC, then I remounted them. Then I tested the airflow with the gizmo Sundstrum includes with the unit and airflow was better than spec.

I don't think blowing the dust off made that much difference. It just appears that a good deal of fine, but still macroscopic dust can collect in there without clogging the filters.

Thank you for sharing the results of you investigation and testing.

 

[Gerald Lawrence]

First I tested the filter warning system and that is working. Since the dust was getting everywhere I blew the filters off directly into the DC, then I remounted them. Then I tested the airflow with the gizmo Sundstrum includes with the unit and airflow was better than spec.

I don't think blowing the dust off made that much difference. It just appears that a good deal of fine, but still macroscopic dust can collect in there without clogging the filters.

I blow out the filters in my overhead air filters and on my Trend. However a long time ago in a dust collector forum it was stated that blowing out filters would defeat the material the filter is made of and let the bad stuff past it. I do not test my filters but do wonder if the increased air flow may not be caused by filter degradation.

 

[Mark Jundanian]

Certainly vigorously blowing through a filter with high pressure air could damage the filter. But I think such a tear would tend to be apparent. I don't think I'm risking any harm with a gentle approach. Still next time I may just remove whatever I can get out by tapping the filter. My goal isn't so much to use the filter beyond its service life, but I don't want to toss one prematurely just because it's making a mess, especially when the loose dust is easily removed. So looks like I have a new regular maintenance item.

 

[Roger Chandler]

I wonder if you had the pre-filters installed? On my SR-500, I blew out one of the pleated filters because I forgot to put in one of the pre-filters, and when I did, the pleated filter got a sizable hole in it. I had to get a replacement for it. I ordered 2 packs of pre-filters, some clear visor protectors, and 3 additional pleated filters to have on hand. Now I want a spare battery for the thing. So far after about 10 months of use, I could not be happier with the Sundstrom SR-500 & 570 helmet combination.

I have only found dust on the pre-filters when everything was installed correctly, and find a light air brush with the air hose will clean off any accumulated dust on those pre-filters, without any damage, but the air pressure needs to be set on low.

 

[Mark Jundanian]

I don't have the pre-filters. Maybe I should look into them?

 

[Mark Jundanian]

So @Roger Chandler , I'm wondering if that pre-filter fits easily in the housing or if it requires a little pressure to close the case? and, does it restrict the airflow very much?

 

[Roger Chandler]

Mark, the pre filters are flat disc filters that sit over the pleated filter, and the outer shell will snap onto the housing with both filters in place. You are definitely supposed to use the pre-filters with the unit. A 10 pack is about $5.00…..well worth the protection, and that is the way the system is designed to work. It does not restrict air flow…..I only use the low fan setting on my unit, as it seems to be more air flow with that than the Trend Airshield Pro I was using prior to my purchase of the Sundstrom SR-500. The high fan setting is way more air flow over my face than I need.

FYI…there are a couple of good youtube videos on the SR-500 that will go over proper proceedure and use, if you will do a search….I found them very helpful.

 

[Doug Freeman]

I have a Versaflow and not Sundstrom, but similar. Can’t get to the actual filter media, so I use a vacuum at the “filter inlet” and tap the filter to loosen dust. It does use a prefilter, more of a thin expanded foam sponge like material. It captures quite a bit of larger dust.

 

[Bill Boehme]

If your PAPR uses HEPA filters then vacuuming or blowing out the dust will damage the delicate HEPA membrane. The damage is on a microscopic level so it isn't something that you can see.

 

[Roger Wiegand]

Years of filtering stuff in the lab (mostly liquids, but I think the principle is the same) taught me that a succession of filters, from coarse to fine permits a much faster overall flow rate than just starting with the fine filter. With most media it's really easy to clog the fine filter, so you want to minimize the amount of material reaching it.

I too suspect that blowing out a HEPA filter will damage it microscopically. It would be interesting if someone with a particle monitoring system could test the number and size of particles getting through before and after blowing one out.

 

[Mark Jundanian]

The Sundstrum has a P100 rating, but I don't know about HEPA.

 

[Bill Boehme]

The Sundstrum has a P100 rating, but I don't know about HEPA.

The 100 designation means that is a HEPA filter rated to remove 99.97% (US, or 99.95% EU) of particles that are 0.3 μm and larger. The letter P indicates that the filter is rated for particles and oil-based fumes. The letter N indicates that the filter is rated only for particles. The letter R on face masks indicates that the filter is rated for particles and oil mists for a maximum of eight hours. I've never seen the R designation.

 

[Daniel Henry]

During a significant part of my 30+ years of industrial working career, I worked with both asbestos and lead. Please don't vacuum nor blow out your filters. Properly dispose of the "used-up" filters. I apologize for this late comment but I'm really new to AAW. I greatly appreciate the emphasis on Safety and Health.

 

[Mark Jundanian]

Not late at all, @Daniel Henry . As a matter of fact I'm expecting delivery of replacement filters in a few days. So I will be changing out shortly.

I am curious to know more about the rationale behind your admonition not to blow out a filter. Not saying it's bad advice, but a lot of people do it. Just looking for more detail.

And are you mostly concerned with PAPR filters of filter in general?

Thanks

 

[Roger Chandler]

If you do use compressed air, make sure its only about 25 psi....higher pressure can and will damage the Sundstrom filters. Mainly, if you do, you're just trying to back the loose dust off, and not do a deep clean. If your main filter has been used for a long while without the pre-filter discs, then new ones are in order I think.

 

[Daniel Henry]

High pressure will potentially damage the filter element as indicated above. When air pressure is used to dislodge the dust, debris, and bad actors in an air filter where is all that "stuff" going? Often times some of it gets on the individual. If an air filter, apr, papr, scba, and the like are used to prevent dust from entering a person's lungs, where does that material go when it is hit with compressed air? I've seen it done. And yes, I have done it years ago. You hold the filter cartridge in your hand and hit it with a shot of compressed air and the junk goes everywhere. Hope this helps. Am I suggest posing this question in a call or email to the manufactures and NIOSH

 

[Timothy Allen]

In other words, make sure you are wearing your PPE (fully functioning and properly fitted) when attempting to blow out dust filters -- right? !