Gas detector tubes are produced by several well-known brands around the world, commonly used for spot-checking or short-term measurement of gas concentrations.
Modern Tube Types
Low-Vacuum Bellows
- ~7 mm tube o.d.
- Larger particles
- Examples:
Draeger Accuro
MSA Kwik-Draw
High-Vacuum Piston
- ~5 mm tube o.d.
- Smaller particles
Examples:
Uniphos ASP-50
RAE LP-1200
Gastec GV/100
Kitagawa 8014-400A
The Draeger Accuro & MSA Kwik-Draw are interchangeable. They have the same volume and tube fit
Low-Vacuum Bellows
– 7 mm tube o.d.
– Larger particles
Pumps Must Have Same:
– Volume Accuracy
– Flow Characteristics
– Tube Fit (7mm= 7mm)
The Uniphos ASP-40, RAE LP-1200, Gastec GV/100, Kitagawa 8014-400A, Sensidyne AP-20S are interchangeable. They have the same volume and tube fit.
Interchangable piston pump
– 5 mm tube o.d.
– Larger particles
Pumps Must Have Same:
– Volume Accuracy
– Flow Characteristics
– Tube Fit (5mm= 5mm)
Agency Approval
Why do several government agencies have statements against interchangeability?
All seem to be based on old 1974 study* using pumps of different design and flow characteristics and mostly are no longer used:
Four orifice limited pumps
one bellows pump
one piston pump
Cohen, F.H., A study of the interchangeability of gas detector tubes and pumps, AIHA Journal 35, 686 (1974).
Conclusions
-Tubes and pumps are interchangeable if design/performance criteria are the same and appropriate leak checks are performed
– Interchangeability should be guided by pump specifications, not by brand name.
– Because the piston pumps tested are equivalent, any new tube designed to work on the Gastec pump will also work on the RAE or Kitagawa pumps, and vice versa.