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Legislation

Carriage of compressed gas cylinders in vehicles is regulated under ‘The Carriage of Dangerous Goods and Use of Transportable Pressure Equipment Regulations 2007’ (CDG 2007); frequently referred to as Carriage Regulations 2007 (CR 2007)

Whether a given load of cylinders is subject to CDG 2007 is determined by a 'Threshold Quantity' calculation; this applies regardless of vehicle weight or load capacity and the calculation is determined solely by the quantity, size and type of gas cylinders carried.

Everyone carrying gas cylinders in vehicles during the course of work must satisfy basic legal safety requirements even if the load does not exceed the 'Threshold Quantity’.

Codes of Practice

British Compressed Gases Association Code of Practice 31 (BCGA CP31) refers to vehicles classed as mobile workshops or service vehicles - i.e. fitted with cylinders for use in or carried on the vehicle.

Vehicles used solely for the transport of gas cylinders are excluded from CP31; the procedures relevant to them are outlined in BCGA Leaflet 1 2005: The Carriage of Gas Cylinders by Road in Cars, Vans and Other Vehicles.

Vehicle Type – Vehicles Used Solely for Transporting Cylinders

• Where possible vehicles should have an open load space e.g. pick-up truck
• Where this is not possible, the load space should be well ventilated
• Under CDG 2007, open windows and vehicle fan-assisted ventilation are not adequate
• If an unventilated vehicle is used the loading doors must be signed:

WARNING: NO VENTILATION | OPEN WITH CAUTION

Vehicle Type – Mobile Workshops and Service Vehicles

Specific ventilation requirements are outlined for these vehicles including:

• Minimum ventilator area of 2% of the vehicle floor area
• Fixed non adjustable ventilation at low level
• Fixed vent, preferably a roof spinner or similar, at high level
• Ventilation should be equally divided between front and rear of the vehicle

Toxic gas must not be carried in closed vehicles unless they are specifically designed for this purpose

Cylinder Segregation from Driver

Where cylinders to be used off the vehicle are carried within a closed vehicle, the load compartment should be separated from the driver's cab by a gas tight bulkhead.

This should be such that it is able to protect the driver from cylinder impact in the event of a traffic accident.

Fire Extinguishers

The Law for small vehicles and vans requires a suitable 2kg fire extinguisher

Dry powder may be appropriate

Vehicle Maintenance

The vehicle must comply with statutory requirements when in use and be properly maintained. Records of maintenance should be kept.

Vehicle Documentation

The documentation required for a journey may vary according to the quantity and type of gas cylinders carried.

Vehicle Signage

It is not a legal requirement to display hazard-warning signs on the vehicle when below the threshold limit.

It is good practice however to display appropriate warning signs on the vehicle when gas cylinders are being carried; they must be removed once the cylinders have been unloaded.

Driver Training

Drivers should be:

• Trained in the hazards and properties of the gases they carry
• Trained in the safe use and handling of the gases
• Trained in the use of vehicle Fire Fighting Equipment
• Conversant with CDG 2007 and relevant Emergency Procedures

Note: ADR training is required for drivers of vehicles below 3.5 tonnes if the load threshold is exceeded.

Before Journey Checks

The driver should ensure the following:

Cylinders	Valves closed & leak checked
	Correctly labelled
	Secured and carried upright whenever possible (Propane must be carried in an upright position at all times. Refer to LPG UK CP27)
	In a closed vehicle loaded in a single layer and constrained to prevent any movement or displacement
	Not projecting beyond the side or back of the vehicle
	Where fitted, gas tight plugs should be in place. Where more than 4 LPG cylinders are carried the driver should carry sufficient spare plugs or caps for use where they are missing on returned cylinders
Equipment	Disconnected from cylinder
Vehicle	Appropriate for use
	Within weight limits
	Road worthy
	Engine stopped for loading and unloading
	Vehicle crew only no passengers
	Ventilation points free from debris and uncovered
	NO SMOKING allowed
Driver	Trained in emergency procedures
	Training current

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Acetylene Gas
 
Acetylene is a colourless gas with a strong natural odour, similar to garlic; it has the chemical formula C2H2.  It burns with a highly luminous flame and has a very wide flammability range when mixed with air. In its free state, Acetylene will begin to dissociate into its constituent elements, becoming unstable; it is therefore the only gas to be manufactured under the constraints of the Explosives Act.

Acetylene Cylinders
 
Acetylene cylinders differ from other gas cylinders in that they do not contain compressed or liquefied gas alone.  Acetylene cylinders contain Acetylene gas dissolved in Acetone absorbed into a porous mass within the cylinder. The porous mass is designed to slow or inhibit any thermal dissociation, usually providing time for emergency action to be taken in the event of mishap.

Uses of Acetylene

Acetylene's chemical and physical properties account for many of its uses.
Achieving a very high flame temperature (roughly 3,300°C when burnt with oxygen) it can be used to weld, cut, braze and solder metals in extreme environments - from great depths underwater to the intense cold of Alaska.
In the laboratory Acetylene is used for chemical synthesis, and in analytical equipment such as atomic absorption equipment, gas and mass spectrometers.

Safe Use of Acetylene in the Workplace

• Avoid mishandling Acetylene cylinders, by dropping, jarring or rolling them (an empty space may develop in the porous substance within the cylinder, allowing ignition to start by mechanical shock)
• Use the correct Regulator
• Use a Flashback Arrestor when using Acetylene with a source of ignition (e.g. in cutting equipment)
• Secure & move Acetylene cylinders with the valve uppermost to prevent Acetone within the cylinder being drawn over the gas.

Storage of Acetylene Cylinders

Consider the use of light reflecting tape

• Acetylene cylinder storage should be:
  • well defined
  • clearly visible
  • accessible
  • signed with suitable warning notices displayed
• Ventilation
  • Ensure permanent high and low level ventilation is provided
• Distance: Cylinders should be stored a minimum of 3 metres away from any fire hazard or heat (e.g. stores of flammable or oxidising materials, radiators & heaters
• Store only the smallest practicable number and size of cylinders
• Return unwanted or unnecessary Acetylene cylinders to suppliers
• Ensure a record is kept of the presence of all Acetylene cylinders

Fire Risk

Decomposition of Acetylene in a cylinder can be initiated by a flashback from welding or cutting equipment,  by exposure to intense heat  or severe mechanical shock (such as a drop from height).  In most situations, if thermal decomposition is initiated but the cylinder is not subject to further movement or impact, the inert filler will eventually arrest the process, although this may take many hours. 

Fire involving Acetylene Cylinders can cause major disruption

Acetylene gas cylinders present a unique hazard as the risk of explosion following heating can remain for an extended period, long after the fire is extinguished and even after extensive cooling has been applied.  Should an unstable Acetylene gas cylinder explode the resulting dangers can include a fireball, large flying cylinder fragments and other debris with the energy to cause serious injury, and structural damage to nearby buildings.

Because of the risk of explosion:

1. 1. A hazard exclusion zone of 200 metres radius may be established when Acetylene cylinders are involved in a fire; this may be enforced for up to 24 hours
2. 2. A high pressure water hose may be directed at an unstable cylinder for a minimum of 24 hours

Think about Fire Safety when locating each Acetylene Cylinder

• Consider the provision of a purpose-built enclosure for the cylinder, equipped with water shower and drainage, in areas where there is a higher risk of fire
• Consider if sufficient local drainage to avoid or minimise structural damage  is available should cylinders be subjected to 24 hours exposure to high pressure water spray
• Consider what would be the effect of the closure of key transport routes
• Consider what your commercial losses would be

Transport of Acetylene Cylinders

• Cylinder valves should be closed
• Any gas equipment disconnected from cylinders
• Leak checked before the journey
• Correctly labelled
• Secured from movement and carried in an upright position at all times
• Preferably in an open vehicle
• In a closed vehicle cylinders should be loaded in a single layer and constrained to prevent any movement or displacement
• Cylinders should not project beyond the side or back of the vehicle
• For small vehicles and vans a suitable 2 kg fire extinguisher should be available
• Maximum quantity of Acetylene gas only without the full need for compliance with ADR requirements is 333 litres/kilograms

 Warning
 
On Saturday 26 May 2007, an explosion occurred in a van travelling along a street in County Durham which resulted in the death of the driver.  The initial investigation established that the incident is most likely to have been caused by an explosion of Acetylene gas from Oxy-Acetylene cutting equipment being carried in the vehicle.

Pam Waldron, HSE’s Head of Operations in the North East, said: "Whilst the investigation continues, it is important that all users of Oxy-Acetylene equipment review their cylinder transport arrangements.  Instruction and training of employees in safe operation, including regular checks of equipment condition and functioning, are needed to prevent any releases.  In addition such gases are best transported properly secured in an open vehicle; if an enclosed vehicle is used, it should have adequate ventilation."

Are you confident that your employees & contractors are working safely with Acetylene?

For advice on compressed gases safety training call:

Proactive Gas Safety on 01606 872864

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