6.2.1 The last gas valve prior to the gas engine
should be controlled by the engine control system or by the engine
gas demand.
All gas engine components, gas engine systems and gas engine
subsystems should be designed to:
-
.1 exclude any explosion at all possible situations;
or
-
.2 to allow explosions without detrimental effect
and to discharge to a safe location. The explosion event should not
interrupt the safe operation of the engine unless other safety measures
allow the shutdown of the affected engine.
6.2.1.1 When gas is supplied in a mixture with
air through a common manifold, sufficient flame arrestors should be
installed before each cylinder head. The mixture inlet system should
be designed to withstand explosions of mixture by means of:
-
.1 explosion relief venting to prevent excessive
explosion pressures. It should be ensured that the explosion relief
venting is installed in a way that it discharges to a safe location;
or
-
.2 documentation demonstrating that the mixture
inlet system has sufficient strength to contain the worst case explosion.
6.2.1.2 The exhaust system should be designed
to withstand explosions of unburned mixture by means of:
-
.1 explosion relief venting to prevent excessive
explosion pressures. It should be ensured that the explosion relief
venting is installed such that they discharge to a safe location;
or
-
.2 documentation showing that the exhaust system
has sufficient strength to contain the worst case explosion.
6.2.1.3 The crankcase of gas engines should be
provided with:
-
.1 crankcase explosion relief valves of a suitable
type with sufficient relief area. The relief valves should be installed
in way of each crank throw and should be arranged or provided with
means to ensure that discharge from them is so directed as to minimize
the possibility of injury to personnel. Refer to SOLAS regulations II-1/27 and 47.2; or
-
.2 documentation showing that the crankcase has
sufficient strength to contain the worst case explosion.
6.2.1.4 It should be ensured that the explosion
of unburned mixture within the exhaust system or the crankcase or
the explosion of mixture within the mixture inlet is allowed without
detrimental effect.
6.2.2 The design of piping on gas engines should
follow the requirements in chapter 2.6 “System configuration”
and chapter 2.7 “Gas supply system in gas machinery spaces”.
6.2.3 The combustion of the gas mixture should
be monitored. This can be achieved by monitoring of the exhaust gas
or combustion chamber temperature.
6.2.4 The exhaust pipes of gas-fuelled engines
should not be connected to the exhaust pipes of other engines or systems.