Because of the physical hazards involved in handling propellants
and controlling high pressure combustion proeesses, certain elementary
safety precautions must be observed in static testing of rocket
engines. During the design, and later, the operation of amateur liquid
rocket engines, the following general safety precautions shou1d be
- The operator should be protected by a suitable barricade located
some distance (at least 20 feet) from the test unit.
- Control of valves during engine ignition and steady-state
operation should be by remote means, which for amateur units is best
achieved by manual control of needle valves via valve stem extensions.
- A large chemical fire extinguisher (or, at least, a plentiful
supply of water) should always be on hand.
- The operator shOuld not view the test unit directly, but should
use a mirror arrangement (somewhat like a periscope) or use a thick
layer of reinforced safety glass attached to the operator's
barricade. REMEMBER, the primary danger is from shrapnel in the event
of engine explosion.
- Separating of fuel and oxidizer storage reduces the fire and
explosion hazard and limits the amount of propellant stowed in any one
- The test stand unit should be barricaded on several sides to
reduce shrapnel effect in event of explosion.
- Valves, pressure pauges, and other components which directly
sense fluid properties should not be located in the operator's
station, but should be on the test stand and remotely read. This rule
does not apply to electrical instrumentation wherein a transducer is
located on the test stand and an electrical readout (such as a meter)
is located at the operator's station (this type of instrumentation is
very expensive and is beyond the reach of most amateurs).
- Warning signals should be given prior to tests (or whenever gas
cylinder valves are open) to notify personnel that the area is
hazardous. A test must NEVER be conducted until the operator has
assured himself that all personnel are behind safety barricades or
- Personnel should be permitted to work in the test area only if
fuel and oxidizer are separated and not pressurized.
- Personnel handling propellants should wear safety equipment such
as gloves, face shields, or rubber aprons. Remember that most fuels
are toxic; do not breathe fuel vapors for even a short time.
- No smoking is ever permitted anywhere near a test area when
propellants are alse present, Remember vapors from hydrocarbon fuels
(such as gasoline) can travel long distances from the test area and
can be ignited at a remote point travelling back to the test stand.
- A check-off list is helpful when conducting a rocket engine
firing and should be made up of both technical events and safety items
to be completed prior to the firing.