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Regulator Use Procedures for Non-Hazardous Gases
This document is intended to serve as a general guideline for the use of
compressed gas regulators. It is assumed that the system or apparatus to which
the gas cylinder is being connected has been properly designed and tested for
the high pressures and other hazards associated with compressed gas. This is not
a guide for the use of hazardous gases or systems using such gases. It is the
responsibility of the operators to obtain the proper training in such
situations. Any reference to hazardous gases is purely incidental. Regulators
for oxygen service require special considerations. Consult your gas supplier and
MSDS. This document should be read completely before proceeding.
Safety Precautions
WEAR APPROVED EYE PROTECTION AND SAFETY APPAREL AS RECOMMENDED BY THE
MSDS.
Know the specific hazards associated with gas to be used. Consult the
MSDS that was shipped with the gas or obtain a copy from Occupational Health
& Safety.
Leak test the system on which the gas is to be used.
Make sure the regulator to be used is suitable for the application. Most
gas company catalogs give this information for both gases and regulators or,
if not, consult the vendors directly.
Categories of Regulators
A single-stage regulator will usually require delivery pressure
adjustment as the cylinder pressure decreases.
Two-stage regulators will usually require no adjustment.
Installation and Operation
Properly secure the cylinder to a stable surface.
Remove the cap from the cylinder.
Make sure the cylinder valve is tightly closed.
Remove the cylinder valve cap or plug if present.
Check the CGA regulator fitting and the fitting surface of the cylinder
valve for damage, especially the threads and seat. If damaged, return the
cylinder for replacement. Remove any loose debris from the threads and seat.
Close the regulator by turning the adjusting knob or handle
counterclockwise.
Close the outlet valve fully in a clockwise direction. If a valve
is not present, one should be purchased.
Connect the regulator to the cylinder. DO NOT FORCE the connection. You
should be able to make the initial connection by hand. If not, then you are
using the wrong regulator, or the threads on the cylinder valve or CGA
connection or both are damaged and should be replaced. Tighten until snug
using a regulator wrench, an open end wrench or an adjustable wrench. DO NOT
OVER-TIGHTEN.
NEVER use lubricants or Teflon tape to aid in the connection or sealing
of the CGA fitting.
Check the cylinder valve for leaks around the thread connections into
the cylinder and the valve handle, using an approved soap solution
(available from gas suppliers). If any are discovered, return the cylinder
for replacement.
Hex nuts on the CGA connection with notches in the middle indicate left
hand threads and are tightened in a counterclockwise direction.
Some regulators require gaskets on the CGA connections. These should be
inspected for wear or contamination and be replaced as necessary. USE THE
PROPER REPLACEMENT GASKET. Do not over-tighten, as this could cause the
gasket to extrude in the gas stream. Replace the gasket at each cylinder
change out.
Use the proper fittings on the outlet of the regulator to the system.
Avoid too many connections. The correct fitting can be purchased from the
regulator supplier. Do not make adapters to get to the proper fitting.
The operator should position himself/herself with the cylinder between
themselves and the regulator. While looking away, SLOWLY open the cylinder
valve in a counterclockwise direction, 1/8 turn. The high pressure gauge
should rise to full cylinder pressure.
Leak check all connections using an approved soap solution or other leak
checking device (hand-held detectors for specific gases, etc.). If leaks are
discovered, depressurize, tighten, then recheck the connections. If you
cannot easily make a leak-tight seal at the CGA fitting, and the problem is
not with the cylinder valve, the CGA fitting should be replaced. These can
be obtained from any gas supplier. DO NOT OVER-TIGHTEN THE CGA CONNECTION TO
TRY AND ACHIEVE A LEAK TIGHT-SEAL.
If no leaks are discovered, open the valve fully to seat the valve, then
close 1/8 turn.
Turn the regulator adjusting knob or handle clockwise to raise the
delivery pressure to the desired working pressure while observing the
delivery pressure gauge. DO NOT EXCEED THE MAXIMUM DELIVERY PRESSURE FOR THE
REGULATOR OR THE SYSTEM.
Check the system for leaks.
Open the outlet valve on the regulator to supply gas to the system.
Delivery pressure may need some adjustment.
Shutdown and Removal
For temporary shutdown (less than 30 minutes), simply close the outlet
valve of the regulator.
For extended shutdown, shut off the gas cylinder valve completely, open
the regulator adjusting valve (to delivery pressure) and outlet valve, and
drain all gas from the regulator through the system. Both gauges should read
zero. Close the regulator by turning adjust knob counterclockwise and outlet
valves.
If replacing the cylinder, follow the procedure for extended shutdown,
remove the regulator from the cylinder, and install the new cylinder as
outlined in the installation procedures above.
In general, a cylinder is considered empty when the cylinder pressure is
2X the usable delivery pressure. Do not draw down below 2 bar.
Source:
http://www.udel.edu/OHS/regulatoruse.html
More resources:
1. Aldrich Technical Bulletin AL-151
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