UFC 4-390-01
23 July 2003
pressure, humidity). Descriptions must be furnished for all
remote control systems. The descriptions should include an
analysis of the consequences of a failure or loss of normal mode,
and describe automatic and manual backup control features
available for emergency recovery or surfacing procedures. Test
data in support of system and component reliability for the
intended service must also be provided. Design information and
test data must be in sufficient detail to permit an independent
evaluation of the adequacy of the controls in their environment,
under all normal and emergency operating conditions.
B.12.1 Remote Control Power Supply. Remote control power
supplies may be manual, mechanical, pneumatic, hydraulic, or
electrical. The choice should be based on reliability in the
environment in which the power supply must function. The
designer should furnish information that substantiates the
reliability of the power supply in the intended environment.
This information may be based either on previous use of the power
supply or on tests.
All critical remote controls must have two independent sources of
power. Failure of one of the power sources should not hinder the
use of the other power source.
B.12.2 Remote Control Monitoring. Remote control systems should
require devices that monitor system status and responses.
Indication of malfunction or failure in a control actuator must
be provided to the operator. The applicant should define the
level of monitoring required based on the criticality of the
system. The monitoring system design should be submitted to the
SCA for concurrence.
B.12.3 Remote Control Actuators. A remote control actuator is
any device or group of devices used to accomplish a desired
control function. The design should be such that the control
actuator is not subject to false alarms or extraneous signals
that produce undesired responses. Switches and controls that are
used to manually energize a control actuator must be located so
that they are not inadvertently energized.
Remote control actuators should be designed to be fail-safe.
Individual remote control actuators should be capable of being
isolated from other remote control actuators that share a common
power supply. For electrical remote control actuators, this
requires either fuses or circuit breakers on all lines connecting
each remote control actuator to the power supply. For hydraulic
or pneumatic remote control actuators, this requires appropriate
check valves or isolation valves on all lines connecting the
power supply to the remote control actuator.
Where a remote control actuator normally operates automatically,
provision should be made to allow the operator to manually
override the automatic control. The manual control should bypass
as much of the automatic control system as is practical.
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