1 Background
This document provides basic guidance on the safe storage and handling of compressed gas cylinders. These guidelines need to be followed in order to protect people, property and the environment from emergencies involving gas cylinders as well as ensuring compliance with relevant legislation.
2 Scope
These guidelines apply to all workers and others who store and handle gas cylinders at the Eersterust Care and Training Centre.
3 Definitions
Asphyxiation – Breathing difficulties (suffocation), loss of consciousness and eventual death caused by an inadequate supply of oxygen to the body.
Flammable gas – A gas that can be ignited in air.
Inert or Noble gas – Any of the six gases helium, neon, argon, krypton, xenon, and radon.
These gases are un-reactive except under certain special conditions.
Non-flammable gas – A gas that is neither flammable nor poisonous but can still cause asphyxia and death.
Oxidizing gas A – gas that initiates or promotes combustion of materials through release of oxygen. These gases can also spontaneously combust/explode.
Short Term Exposure Limit (STEL) – Maximum concentration of a gas that a person can be exposed to for a 15 minute period. Only 4 such exposure periods can occur within an 8 hour day and 1 hour break is required between exposure intervals.
Time Weighted Exposure Limit (TWA) – Maximum concentration of a gas that a person can be exposed to for 8 hours per day over a 5 day working week.
Toxic gas – A gas that is poisonous or capable of causing injury or death, especially by chemical means.
Upper and LowerExplosive Limits (UEL and LEL) – Upper and lower concentration (in %) limits for which a particular gas is explosive in air.
4 Types of Gases
There are three types of gases commonly supplied and used:
Compressed Gases – Nitrogen, Oxygen, Air, Carbon Dioxide, Helium
- Liquefied Gases – LPG, Liquefied Nitrous Oxide
- Dissolved Gases – Acetylene
5 Types of Gas Cylinders
In general, there are three types of gas cylinders:
- High Pressure Cylinders – High pressure cylinders come in a variety of sizes, see Figure 1.
Some examples of gases supplied in High pressure cylinders include Nitrogen, Helium,
Hydrogen, Oxygen and Carbon Dioxide. - Low Pressure Cylinders – Low pressure cylinders come in a variety of sizes, see Figure 2.
Some examples of gases supplied in low pressure cylinder are LPG and refrigerant gases. - Acetylene Cylinders – aggregate filled and acetylene is dissolved in acetone to get
sufficient product into the cylinder. See Figure 3.
Acetylene is in a class of its own as the cylinder is filled with an aggregate material and dissolved
in a liquid medium (acetone)
6 Risks and Hazards from Gas Cylinders
Gas cylinders can be hazardous due to both their physical (size and weight) and chemical characteristics. Hazards from gases are also subject to the chemical properties of each gas.
These may be one or more of the following:
Fire or explosion from the release of flammable gases near ignition sources (e.g. acetylene
or LPG). Refer to SDS for Upper and Lower Explosive Limits (UEL and LEL)
Spontaneous combustion from oxidizing gases (e.g. oxygen or nitrous oxide)
Exposure limits for all gases, especially toxic or corrosive gases (e.g. anhydrous ammonia);
refer to SDS for Time Weighted Exposure Limit (TWA) and Short Term Exposure Limit (STEL)
Asphyxiation from non-toxic, non-flammable gases by displacement of oxygen (e.g. nitrogen, carbon dioxide or argon)
Incorrect storage
Leaks
Faulty equipment/connections
7 Storing Cylinders
Gas stores should be located outdoors, preferably in a secure, cage protected from sunlight.
Storage indoors is not recommended unless the building has been designed for that purpose with
appropriate fire rated walls and ventilation. Where gases are stored indoors, additional safety considerations and control measures need to be given consideration.
8 Safe Handling Practices
Most accidents or injuries involving cylinders happen when moving or handling the gas cylinders.
Large gas cylinders (e.g. G or F sized cylinders) can be bulky, heavy, and awkward to handle, they
require special care and equipment in handling and securing so they don’t fall or tip over and
cause injury. Anyone involved in the handling of gas cylinders should undertake some basic induction training or have read the Safe Work Procedures relating to the transport, storage and use of Gas Cylinders. Wear protective footwear, safety glasses. Gloves are also recommended.
Securely install the valve protection devices when the cylinder is not in use, such as caps or
guards. EXEMPTION: G size cylinders will not have a protective cap or guard fitted.
When moving cylinders, DO NOT roll or drag them. Ensure that an appropriate mechanical
handling device is used (Figure 11). Secure cylinders upright to a proper hand truck or cylinder
cart with a restraining strap designed for the purpose. Cylinder size E and greater shall be handled
using mechanical assistance.
Contact your gas supplier if more sophisticated handling of cylinders is required.
DO NOT lift by the protective cap. If a cylinder does not have a handle then use mechanical
assistance to move it.
DO NOT restrain cylinders around their necks or valve – restrain them around the main cylinder
body at a height that will prevent them from falling over, i.e. 1/2 to 2/3 the height of the cylinder.
Avoid dropping or knocking cylinders about. Prevent damage to cylinders from impact from other
objects (e.g. crashing into other cylinders). Some cylinders (e.g. acetylene) may react violently after being excessively shaken, heated, or knocked.
Cylinders should NEVER be used as rollers to move other objects.
9 Using Gas Cylinders
Always use gas cylinders in well ventilated areas. DO NOT use gas cylinders in confined
spaces unless qualified to do so and the appropriate PPE is used.
Know the gas you are using and possible reaction products. Additional mechanical
ventilation may be required. Seek expert assistance in designing and installing mechanical
ventilation systems.
Ensure the correct regulator is used for the purpose.
Ensure there is a suitable emergency response procedure in place.
Wear appropriate PPE for the gas been used, refer to SDS.
Ensure connections, fittings and lines are leak tight and suitable for use.
Ensure that flammable and oxidising gases are not used near ignition sources.
Disconnect empty cylinders from equipment to avoid backflow issues
Always close the cylinder valve when not in use.
DO NOT use an empty cylinder as a waste receptacle.
Fit non-return valves in line if required
DO NOT use a gas cylinder that shows evidence of damage or corrosion. The gas cylinder
is a rented item; its integrity is the responsibility of the gas supplier.
If the cylinder contents cannot be clearly identified, DO NOT use it. Return it to the supplier
NOTE: If a cylinder shows frosting around the valve than the flow through the
system is too high or there is a significant leak in the system. If a high flow rate
option is required, consult your gas supplier for the best solution.
10 Transporting Gas Cylinders
10.1 Transport within Buildings
Cylinders shall be transported within buildings according to section 10.2.
Transporting cylinders between floors of a building shall be done in the lift alone. No person is to
travel in the lift with the gas cylinder. The cylinder trolley shall be secured to the lift hand rail to
prevent it from falling over. Ideally a sign should be used across the entrance of the lift to prevent
others entering the lift while the cylinder is in transit.
Secure the cylinder immediately once arriving at the usage location.
10.2 Transport with Vehicles
Gas cylinders used in the field may require the use of a vehicle to get them to the field site. Where
possible, have your gas supplier deliver the cylinders directly to the field site. If a vehicle is
required to transport cylinders, then it shall be done as follows
Gas cylinders shall only be transported on an open back utility OR in a utility back canopy that is
separate from the main body of the vehicle.
Ideally cylinders should be transported standing up and firmly secured. Flammable and Liquid
withdrawal cylinders should always be transported in upright position.
If cylinders are transported lying down than suitable support devices are required to prevent the
cylinders from rolling. Also settling time will be required for the cylinder before use, refer to section
Remove the gas cylinder(s) from the vehicle immediately on arrival to destination and secure them
appropriately.
DO NOT carry gas cylinders of any kind in the passenger compartment of a vehicle.
