[Ferro List] "Respirators are an appropriate topic for FC workers"

[twobends at charter.net]

Hi KB,

  Respirators are a good thing in many fields, most industries do not wish to alarm their 
workers of the long term consequences of exposure.  If you don't drop dead as an obvious 
result, they are very relaxed about toxic substances.  The supplier I purchased silica fume 
from said you can much easier obtain silica fume/cement premix locally.  How many people 
using that take good precautions when it is 'just' an admixture?

  While the 3M 501 welding and grinding helmet system is over $2000, I purchased mine in 
very good condition for about $500 on ebay, saved a bundle on filters and supplies too.

  For dust, not welding glare, they have just the clear face mask (it will accept a welding face 
mask on the exterior) that mounts on their 501 helmet.  It flips up out of the way for comfort 
and convenience.  No need to dismount the rig to talk on the phone, read or drink 
something.
   They would be  less ($1700?) and I bought a new one on ebay for $25 minus the belt 
pack.  That would have the blower, battery and hose that fits into the rear of the helmet.  
The battery lasts 8hrs or  more.

  These flow the air over your head, down your face and exit around the neck.  Very 
comfortable.

  These can be fed without outside air via an air compressor, oil-less or or with breathing air 
quality filters, on a 3/8" line.  To use the turbo type air pressure reducer, mounted on your 
belt, you need 5HP. That is a bit wastefully of power, but if will deliver air at + or - 20 
degrees F.  Very nice on hot or cold days if working outside.  Bought two of those on ebay 
for only $25 each too. $125 new.  The unadjustable ones are cheaper and conserve air.

  For indoor work with a little less freedom of movement, i will be hooking up a furnace 
exhaust fan with a dump valve to set the flow to my comfort.  These types of straight blade 
blowers deliver enough pressure to push air 75' down a 2" pipe.  All your 90% plus efficient 
furnaces and water heaters use these thermoset plastic blowers for exhausting spent 
combustion air.  Perfect for this use.  You can scavenge them for free, I paid $2 for one this 
fall, so they are cheap.  You would transition your 2" feed pipe to 1.5" at the point of use.  
Vacuum hose is very flexible and would be attached to your waist belt and hook up to your 
helmet hose right there.
  A regular squirrel cage blower is not suited to this duty, too low a pressure.  Axial fans like 
computer fans even more so.  They would not blow anything down a 2" pipe.

  For $5-10 you can get the disposable clear plastic hoods on ebay that are designed to be 
fed by a large hose too, but they will not be anywhere near as comfortable as the 501 head 
gear.  They have replaceable face guard shields to protect the main visor.  Here is the link:

3MTM Belt-Mounted Powered Air Purifying Respirator (PAPR) GVP-Series

http://products3.3m.com/catalog/us/en001/safety/occ_health_safety/node_GSNXG6M6FYbe
/root_GST1T4S9TCgv/vroot_5SDD44F7DZge/gvel_WRBPCLK8SWgl/theme_us_ohes_3_0
/command_AbcPageHandler/output_html

Poke around on the 3M website, many models.  The 900 series is a cape seal type for 
greater protection, as if you were gunniting or sandblasting.  They have a new sandblast rig, 
had their old one and it worked great also.


Alan