Safety of Gas CylindersSafety of Gas Cylinders

Presentation by Philip Gallimore Media Representative for IOSH North Staffs

1

Representative for IOSH North Staffs and South Cheshire District Feb 2014

Some gases you may know

• Air gases: oxygen, nitrogen and argon• Rare gases: helium, krypton, xenon and neon• Hydrogen, carbon monoxide, carbon • Hydrogen, carbon monoxide, carbon dioxide and nitrous oxide• Acetylene, methane and propane

Production of Gases

• Air gases (oxygen, nitrogen and argon) are mostly produced at cryogenic temperature in “Air Separation Units“. In smaller quantities and lower qualities other technologies (Pressure Swing Adsorption technologies (Pressure Swing Adsorption or membranes) are used to produce oxygen and nitrogen at the customer sites.

Future innovations-• Healthier Life: food preservation, hygiene,

new medical gases and aerosol therapy • Communicating World: electronics and

semiconductors, optoelectronics • Sustainable Environment: clean • Sustainable Environment: clean

energies, waste control, more efficient processes

Supply by cylinders• Smaller quantities of gases are

supplied in gas or liquid cylinders.• Around 100 million cylinders are in

circulation worldwide.

Gases in Cylinders• Gases

– Over 130 individual gases and liquids are packaged in cylinders

• Gas mixtures– Infinite variety of mixtures varying from PPB to – Infinite variety of mixtures varying from PPB to

percent concentrations– Components from 2 to >50

Three Types of Packaged Gases

• Gases are packaged into cylinders in a variety of ways– Compressed Gas ( e.g. Nitrogen)– Liquid and gas ( e.g. Carbon Dioxide)– Liquid and gas ( e.g. Carbon Dioxide)– Gas in solution ( Acetylene Only)

Transport classes for gases is Transport classes for gases is simplest:simplest:

Gases are all UN class 2 substances• FLAMMABLE 2.1

• NON-FLAMMABLE 2.2• NON-FLAMMABLE 2.2

• TOXIC / CORROSIVE 2.3

Flammable Gases• Acetylene

• Hydrogen• Hydrogen

• Propane

Non-Flammable Gases• Nitrogen• Argon• Helium• Helium• Carbon Dioxide• Oxygen

Toxic Gases

ChlorineHydrogen ChlorideAmmonia

Hazards relating to Cylinder Gases

• Weight• Pressure • Gas properties

Cylinder Weight

Cylinder construction Cylinder construction means that cylinders means that cylinders are heavy even when are heavy even when are heavy even when are heavy even when

empty!empty!

Construction of Gas Cylinders

High Pressure Cylinders Low Pressure CylindersAcetylene and LPG

Handling - Moving Cylinders

Lift by hand using valve guard (10 litre cylinders)

Roll cylinder on solid clean floor (50 litre cylinder)

Churn by valve guard (110 litre cylinders)

Ideally use a Cylinder Trolley

Secure Cylinder in trolley with in trolley with chain, strap or bar

Manual Handling Hazards -Traps Falling Cylinders Pressure

Never attempt to catch a falling cylinder

WEAR

Cylinder Identification

• Because the colours can be confusing• The only way to identify a gas cylinder is

by its label

Marking and Labelling of Cylinders

• Hazard Label• Gas

• UN Number• UN Number

• Mass of cylinder and Tare weight

• Date of next Inspection

Pressure is the Hazard which is common to all Compressed Gases

• Pressure is stored energy• Some units of Pressure are

– Pounds per Square Inch or PSI– Bar– Bar

• Atmospheric Pressure is the pressure on the earth created by the gases above us

• Modern cylinders typically are supplied with 200bar pressure and some are 300bar

Valve - used to control gas into and out of Cylinder

CO2 Bursting Disc

Relief Valve on LPG

Hole reduced to 4mm

Using the gas - Connections

Seals on Dome

Seals on Washer Seals on Washer

Left Hand thread for Flammable Gases -note cuts in nut

Right Hand thread for Non Flammable Gases

Make connections hand tight and then secure with spanner

Ensure connecting pipe work is rated for pressure required

Pressure Regulator

Some cylinders have the pressure regulator built into the valve so you don’t need a separate regulator

Summary of Use

•Check Label

•Access the valve outlet

•Check sealing faces for dirt, oil, damage

•Fit Pressure Regulator (finger tight then 1/4 -1/2 turn with spanner)

Welding Set up

Welding GasesOxygen - never allow oil or grease to come into contact with valve

outlet or fittings.

- never use equipment not cleaned or designed for oxygen service.

Acetylene - if the cylinder is involved in a fire or has suffered a flashback and NO flashback arrestor fitted then the cylinder could suffer acetylene decomposition.cylinder could suffer acetylene decomposition.

- if an acetylene cylinder becomes hot or starts to vibrate then evacuate the building immediately.

- call the Fire Brigade they have procedures for dealing with acetylene in fires

- New requirement that all acetylene cylinders must be fitted with flashback arrestors and non return valves

Backfire and FlashbackBackfire is when flame burns back into the blowpipe often with a loud bang.

Caused by blocked nozzle or holding torch too close to work piece.

Remedy switch off and examine nozzle.

Flashback is when one gas enters the other hose and then ignites causing damage to the equipment.

Caused by incorrect purge of equipmentCaused by incorrect purge of equipment

Remedy proper training and the fitting of flashback arrestors.

10L CO cylinder explosion

Praxair Fire 2005

Tyre fire on vehicle carrying LPG cylinders

Emergency ProceduresEmergency Procedures

All the major Industrial Gases suppliers operate a 24/7 Contact Point in the event that a cylinder is involved in an incident or accident. Please contact Your supplier.

33

bcga.co.uk

• Produces documents for users e.g.

• RA for oxy ace use• Leaflets on carriage • Leaflets on carriage

etc• Go and look for

yourself!

Thank You

The EndThe End