[ RadSafe ] Removing ductwork

Tam Huynh thuynh at isotopeproducts.com
Mon Apr 10 15:58:14 CDT 2006

We treat them as contaminated materials waste. Before you work with it,
make sure:
1) Take wipes and counts it to determine the nuclide and total activity
in the pipes

2) Connect one ended with flex-hose in to the ventilation or hood 

3) Use paint brush and paint roller to coat on the inside surface from
other   end. If the pipe is too long, adapt it with a long extension
stick, or you can remove a partial of ducting where are already painted,
and work through the end. A coat may keep contamination in fixed 
This work requires a Qualified Rad Worker to do these parts. Also make
sure the wipes are taken and counted after the coat is dry. 
If contamination is fixed, you can train the sheet metal workers to do
the rest, but a Rad Worker must be present all the times to observe and
support the Sheet metal workers

4) When all the metal pipes are removed, take wipes and counts it again.
If it is totally not removable, then the pipes can be slowly flattened
and entered to a container, and shipped as it. 

5) A respirator (if you are qualified wearer), or a heavy duty dust mask
is required.

Hopefully, my instruction may help you to do the job.

If you have any other questions regarding of this work, please let me

Good luck on your mission. 

Health Physics Dept. 
Tam Huynh 


-----Original Message-----
From: radsafe-bounces at radlab.nl [mailto:radsafe-bounces at radlab.nl] On
Behalf Of NORTH, Ralph
Sent: Thursday, April 06, 2006 5:45 AM
To: radsafe at radlab.nl
Subject: [ RadSafe ] Removing ductwork

What is your policy regarding allowing sheet metal workers to disconnect
ventilation ductwork/pipes with residual radioactive contamination (100
- 2000 cpm) on the inside (outside surface of ductwork is clean) from
contamination-free fume hood or ceiling? Isotopes are H-3, C-14 or
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