Risk of explosion due to escaping combustible gas or overheating of gas cylinders. Risk of injury caused by burns to skin and eyes. Risk of frostbite to body parts caused by escaping gas and by touching components near the valves when empty - AS00.00-Z-0018-01A
Remove any sources of ignition. Wear heat protective gloves. Ensure that the work area is adequately ventilated.
Model 000.001, 957 with code MS8 (Natural gas engine)
Model 211, 212, 245 with code 924 (Bivalent natural gas drive)
Model 242 with code 924 (Bivalent natural gas drive)
Model 901, 902, 903, 904 with code MS7 (NGT (Natural-Gas Technology) Sprinter)
Model 906 with code MZ2 (Natural gas engine M271)
Model 956 with code M2H (Engine M936G, 222 kW (302 hp), 1200 Nm)
Potential risks
Risk of explosion
There is a risk of explosion when natural gas escapes from the system (e.g. due to a leakage) or in case of overheating of the gas cylinders.
Smoking, fire and open light sources are prohibited:
- in the vicinity of the refueling point,
- in the vicinity of the engine compartment,
- in the vicinity of the gas reservoirs,
- in the vehicle parking hall or the workshop.
Risk of frostbite
When gas cylinders filled with natural gas are emptied, the expanding natural gas cools down to such an extent that there is a risk of frostbite when coming into contact with components close to the valves.
Risk of poisoning and asphyxiation
There is a risk of poisoning and asphyxiation if natural gas is inhaled when high gas concentrations are present in the surrounding air. Particular attention must be paid in this respect to the potential enrichment of natural gas in closed environments.
Safety precautions/instructions
Maintenance and repair work may only be carried out by specially trained personnel.
Any vehicle fitted with a natural gas system and parked on the premises of the workshop must be provided with an easily visible warning of the presence of a natural gas system.
Natural gas is lighter than air and may under certain conditions accumulate in the air. For this reason, vehicles fitted with a natural gas system on which the gas shutoff valves are not closed and the gas lines are not emptied may only be parked
- at places at which an air exchange takes place at least 3 times an hour.
In workshops, adequate ventilation openings must be provided in the roofs of the shops to ensure that any escaping natural gas is able to rise up and escape to the atmosphere without risk.
Before commencing work, ensure that all sources of ignition have been removed. Ensure adequate ventilation of the immediate area around the vehicle.
Adequate ventilation means an exchange of air at least 3 times an hour at a distance of 3 meters from the gas shutoff valve.
Close the gas shutoff valves at the gas cylinders before commencing repair work.
After closing the gas shutoff valves, empty the gas lines by running the engine.
The gas lines are sufficiently emptied when the engine switches to gasoline operation or stops by itself after running at idle speed for several minutes.
Vehicles fitted with natural gas systems on which the gas shutoff valves remain closed and the gas lines have been emptied can be handled in the same way as vehicles that operate with gasoline; provided that
- the gas shutoff valves remain closed,
- the gas lines are emptied and
- the gas cylinder cannot reach a temperature
in excess of 60 °C.
Work which involves any risk of ignition is only permissible on vehicles with natural gas systems after special safety precautions, e.g. closing gas shutoff valves, have been taken to prevent gas from escaping and to prevent the heat from increasing the pressure in the gas cylinder or in the gas lines. If applicable, the gas lines must be emptied and the gas cylinders removed.
If there is a risk that gas cylinders filled with natural gas may acquire a temperature of more than 60 °C when placed in driers for coating material (e.g. when painting), they should be removed prior to drying. After performing work on the components or gas lines of the natural gas system, a leak test must be carried out. The regulations regarding the leak test vary between countries. Please refer to the national legislation for the specific regulations.
The procedure for detecting leaks in a natural gas system must avoid any risk of igniting gas that may flow out.
Leak detectors that can also perform gas measurements far below the explosion threshold are especially suited as gas measurement and warning devices. A leak detecting spray is used for precise location of leaks.
Natural gas can cause frostbite injuries. Protective leather gloves should be used if necessary.
Discharge area:
You should avoid discharging the gas to the atmosphere - if possible - because natural gas is a greenhouse gas. Furthermore, discharging may also disturb the neighborhood. If discharging cannot be avoided, the specifications from the vehicle or system manufacturer must be observed.
Relieving gas systems by means of discharging may only be performed outside. A marked area of approx. 10X10 m is required for relieving the gas system. No other vehicles may be located in this area during the process and no other work may be performed.
Storage area for removed and non-inerted gas cylinders:
The discharge area should preferably be equipped with a lightning protection system (lightning rod). Alternatively, it can be stated in the service instructions that relieving the gas system is not to be carried out when there is the risk of a thunderstorm. The discharge area should have a way to ground the vehicle, e.g. by using a steel rod hammered into the ground.
Special considerations for CNG:
If the discharge area is partially or completely roofed over, you must ensure that the escaping gas can flow freely upwards. Removed and non-inerted gas cylinders should not be stored in the general maintenance and repair area. The storage area can also be located outside. The storage area must be marked and access to the bottles can be restricted, e.g. by means of a tightly-worked chain link fence. In any event, make sure that the gas can mix freely with the ambient air.