Home Podcasts THMG090 – Cylinders, Part II

THMG090 – Cylinders, Part II


In this episode, Bob and Mike continue their discussion of cylinders.

Complete Show Notes

4:20 Cylinder Standards and Laws

  • Most of these laws are developed by the ISO (International Organization for Standardization)
  • Valving tells you more about what’s in the cylinder than anything else
  • Gas cylinders are monitored by the United States DOT
  • 49 CFR, Section 173 mandates the use of hazardous materials placards during shipment
  • OSHA creates and enforces laws protecting workers who handle cylinders and regulations surrounding the cylinders themselves

6:45 Compressed Gas Association (CGA) Numbers and the Code of Federal Regulations (CFR)

  • We need to be able to assess the situation – how are they being stored? Are they immobilized? – this is all covered in CGA 3.4.4 and 29 CFR 1910.101b
  • We need to be able to see if something’s not right and prepare to address those issues
  • CGA 3.6.6 – Determine whether the cylinders are being stored near highly flammable substances
  • CGA 3.5.1 – Are the cylinders being stored away from electrical connections, gas flames, sources of ignition, flammable solvents, combustible waste materials, etc.?
  • CGA 3.3.3 – You must have flammable gasses separated from oxidizing gasses within the storage are
  • CGA 3.5.3 – Are oxygen and fuel cylinders separated by a minimum of 20 feet when in storage?
  • These are federal regulations – your state and local regulations may be different
  • These are the minimum regulations – you can make things safer, but you can’t fall below these standards
  • CGA 3.5.5 – storage rooms have to be fire resistant and shouldn’t be located in sub-levels (like basements)
  • CGA 3.3.7 and 29 CFR 1910.1b – They should also be in a secure area with temperatures below 125 degrees Fahrenheit and away from sources of ignition
  • Essentially, we want to keep them in a cool, dry, ventilated area
  • Cylinders also need to be stored away from incompatibles – for example, you don’t want a peroxide cylinder next to an inorganic cylinder
  • If there’s rusting, you’re dealing with a thinning of the wall – these walls are specifically designed for really high pressure (i.e. 3,000 psi) – the air is looking for a place to get out

13:15 Cylinder Valving

  • Provides you with some of the most important information you can gather from the cylinder
  • There are a ton of different types of valves out there – impossible to talk about all of them
  • Condensed Compressed Gas Handbook is a helpful resource – full of helpful information on valving (you can also use your phone)
  • Valves and threading
    • The valve will be stamped with a number – you’ll also see the threads
    • Threading tells us a lot – regular vs. reverse, inside threads, outside threads, etc.
    • Look at the neck and how it’s tied into the cylinder
    • Look at the on/off valve on the actual valve – this also gives us a lot of helpful information
    • POL valves have a notch in the nut – quick way of identification
  • Pressure reduction devices
    • We’re not concerned about vacuum breakers since we’re not dealing with tankers
    • You may have a spring-loaded breaker (burps and recedes) or a rupture disk (bursts)
    • You’ll sometimes see thermal blow-offs – often happens if cylinders are stacked

17:15 Specifics on CGA Numbers

  • CGA numbering allows for standardization across cylinders, valving, and products that connect to valves
  • Compressed gasses that come out of cylinders are required to go through very specific valving
  • Some gasses only have one type of valve, while others have multiple types to choose from
  • Valves are regulated based on what their task is and the type of cylinder they’re connected to
  • CGA number is stamped on the side of the valve – they’re usually made of soft brass that can be stamped easily
  • You can refer to CGA numbers in the Compressed Gas Handbook or just Google it – always check multiple sources to make sure the information is correct
  • Looking up the CGA number helps us classify what’s probably in the cylinder and allows us to figure out what the cylinder was designed to hold

23:15 Medical Gasses

  • Cylinders designed to hold medical gasses have a very unique set of valving
  • Pin index connection – system that makes it impossible to cross-thread the valve
  • These valves have holes in them with pins that line up on the adapter – this means only that specific adapter made for that specific gas can attach to that valve
  • If they don’t match up properly, you can still remove gas, but there’s no way to get into the regulator
  • Designed to ensure someone isn’t inadvertently given the wrong medical gas
  • There are specific CGA numbers dedicated to medical gas cylinders

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