ENGINEMAN 1 & C
ones described above except that they are practic-
ally odorless and can cause freeze burns.
During all primary maintenance or industrial
uses of halocarbons such as flushing or recharg-
ing refrigeration or air conditioning systems, the
following good engineering precautions are
7. A medical department representative, who
is trained and knowledgeable in the physiological
effects, prescribed first aid and emergency treat-
ment methods for halocarbon mishaps, should be
alerted to the maintenance action being performed
and standing by for quick response.
1. Strict compliance with NSTM gas-free
Engineering directions for entry into enclosed or
confined spaces, and close adherence to standard
operating procedures for all halocarbon
8. An emergency eyewash/shower system in
the immediate vicinity of all halocarbon opera-
tions should its use be required. Where a perma-
nent system is not available, a portable system of
5-10 gallon capacity should suffice. Only potable
water should be utilized for this purpose.
2. Tested and operational ventilation systems.
Availability of portable equipment to provide in-
take fromand exhaust to the atmosphere (not
recirculation) sufficient to maintain halocarbon
concentration at acceptable limits throughout the
whole maintenance action. (Example: The limit
for continuous exposure to the vapors of Freon
113 is 1000 parts of solvent per million parts of
air. This limit will be reached by evaporation of
approximately 100 milliliters (less than 1/2 cup)
of solvent in a 10 × 10 × 10 ft. space). Local
exhaust ventilation capable of maintaining a
minimum capture velocity of 100 fpm over the
face of the container or operation is normally
required in order to maintain the vapor within ac-
ceptable limits. Note: Absolutely NO venting of
halocarbons below decks shall be permitted.
9. Ships emergency rescue teams (e.g.,
Flying Squads and repair parties) familiar with
the hazards of halocarbons and trained in air-
supplied respirator requirements when involved
in halocarbon rescue operations.
10. The performance of hot work is pro-
hibited from halocarbon work areas, due to the
potential decomposition of halocarbons into more
As stated earlier, in high concentrations,
halocarbons are toxic chemicals. Any handling or
usage of these chemicals requires the following
minimum personal protective measures:
3. Positive pressure emergency breathing
devices with supplied air available in the space for
instant donning and egress in the event of a
Full-length face shield or chemical workers
Apron or coveralls (both may be required)
Elbow length gloves
Boots or booties
Clothing and equipment must be im-
pervious and resistant to halocarbons.
4. Established two-way communications be-
tween the halocarbon pump at the bulk source and
the equipment being filled, cleaned, or flushed.
A backup sound powered system is recommended.
Note: Non-impervious clothing which
becomes wet with halocarbons must be
immediately removed and not reworn until all
traces of the chemical are removed by cleaning.
5. Verification of filling and flushing system
integrity by leak testing (e.g., a pressure drop test)
before halocarbon operations commence.
CHARGING THE SYSTEM
6. A minimum of two people should be sta-
tioned in the space, with a safety observer (tender)
in the vicinity of the egress route if available.
Rescue equipment (as necessary) to quickly
remove personnel from the space in the event of
an emergency. (Rescue personnel should also be
equipped with protective clothing and positive
pressure respiratory protection.)
Information concerning the charging of
refrigeration systems may be found in Naval
Ships Technical Manual chapter 516. The amount
of refrigerant charge must be sufficient to main-
tain a liquid seal between the condensing and the
evaporating sides of the system. When the com-
pressor stops, under normal operating conditions,
the receiver of a properly charged system is about
85% full of refrigerant. The proper charge for a