INDG380 TREAD SAFELY - HSE

machinery safety
14
Tread safely machinery safety
Section 9 Tyre inflation-testing machines
Inflated tyres contain very high levels of stored
energy. If this is released suddenly through failure
of the tyre it can cause serious injuries. Inflationtesting
machines must be designed, maintained
and operated to ensure that the risk of a tyre
Table 5 Hazards and safeguards for tyre inflation-testing machines
Hazard Safeguard
bursting is minimal. They should also be fitted with
strong, rigid safety guards to protect the operator
from injury in case an inflated tyre bursts. Apply the
safeguards in Table 5.
Foot trap from If there is a trapping hazard provide a fixed chock or similar restraint to
descending tyre lift prevent any part of the tyre lift approaching closer than 100 mm to the floor.
Traps at chucks and Ensure operating controls are positioned at a safe distance from the
reciprocating flange plates trapping zone.
Ensure a self-centring three-position control valve is fitted. It should have a
spring-biased set position and should shut off the air supply to both sides of
the pneumatic cylinder when the operating control is released.
Vent the machine fully before changing plates.
Tyre burst/sudden Limit the maximum air pressure available at the machine to the minimum
release of pressure necessary for the tests carried out.
Ensure the machine is designed to apply the inflation pressure in sequential
steps, ie designed to prevent the higher-pressure settings being applied unless
the lower-pressure settings have been selected first.
Fit a suitable warning device incorporating a flashing light to indicate when the
higher-pressure range has been selected.
Limit the maximum inflation pressure on a car tyre inflation-testing machine to
no more than 4 bar (59 psi).
Limit the maximum inflation pressure on a truck tyre inflation-testing machine to
no more than 7 bar (102 psi). If higher pressures are absolutely essential the
machine will need to be enclosed in a specially designed and constructed blast
protection enclosure. Get specialist advice for this.
Provide strong, rigid guards designed to protect the operator from injury if a
tyre bursts. They should be positively interlocked to ensure air pressure equal
to or greater than 3 bar (44 psi) cannot be applied to the tyre until the guard is
fully closed. The guard should incorporate a viewing panel to allow the operator
a clear view of the tyre through it. Keep the panel clean.
On a car tyre machine the interlock should be arranged to ensure that the tyre
automatically deflates as soon as the guard is moved out of the operating
position.
On a truck tyre machine the guard should lock in the operating position and the
interlock should prevent air pressure being applied to the tyre until the guard is
locked in that position. The guard and machine controls should be such that it
is impossible to operate the machine while the operator’s body is inside the
guarding system.
Ensure operators never touch or make contact with a tyre when it is inflated to
above 5 bar. Any inspection carried out when this pressure is exceeded should
be entirely visual. The operator should not touch the tyre.
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