TM 5-814-3/AFM 88-11, Volume III
e. Safety of the operator. Design of the facility should meet all OSHA requirements and should never
require the operator to risk safety for the sake of operating the system.
Materials handling and storage. Adequate space should be provided for storage of process
chemicals, spare parts and machinery. Also, provision should be made for the handling and transportation of
process materials, spare parts and maintenance equipment.
19-3. General safety considerations.
The designer must be aware of the occupational and public health hazards associated with plant operations
and maintenance, and provide the safety features to control such hazards in accordance with existing criteria.
These hazards include mechanical equipment; open pits and tanks; electrical components; toxic, infectious
and flammable materials; and potential oxygen-deficient situations.
a. Safety features in plant design. The safety features listed below are minimum, general requirements
and are not intended to be all-inclusive. For detailed requirements, refer to the applicable standards.
(1) Assure adequate ventilation in wet wells and dry wells. The chlorine storage area will be separated
from the feed area and from the remaining plant areas. Mechanical exhaust ducts for chlorine storage rooms
and the chlorination room will extend from near the floor level and exhaust outside the building. The design
will allow for provisions of adequate make-up air. Design must conform to the requirements of chapter 17.
Positive mechanical ventilation will be ample in grit and screening chambers as well as in the wet and dry
wells. Fan capacities must be sufficient to effect a complete change of air every 2 to 5 minutes. Emergency
generators with internal combustion engines will have their exhaust vented outside of the building to prevent
carbon monoxide buildup during test or emergency use.
(2) Fencing and guard rails will be provided for open tanks, hatchways and other locations when needed.
Stairs will be used for access to pump rooms in preference to vertical ladders. However, when vertical ladders
cannot be avoided and their length exceeds 20 feet, they will be equipped with a ladder-climbing device, a
hoop cage, or offset landings.
(3) All electrical wiring will be properly insulated and grounded. Explosion-proof equipment will be
provided for enclosed or confined areas where explosive vapors, fumes or gases may accumulate; 110 volts
or less for control circuits is desirable in such areas.
(4) Guards will be provided for all exposed, moving parts of pumps and equipment. Hoists and rails for
removal of heavy equipment will also be provided for operation and maintenance purposes.
(5) The plant will be enclosed as necessary to protect the public and the facility.
(6) The public water supply must be protected to eliminate the possiblity of contamination by cross-
connections with sewage or sludge piping. This will be achieved by a vertical, positive air gap of no less than
2 inches between the inlet and the outlet levels of a fixture. The water line utilized for plant washdown will
be provided with a backflow-prevention device. Refer to AFM 85-21 for operation and maintenance of these
devices at Air Force facilities.
(7) A potable, hot and cold water supply will be provided through a mixing faucet. Dressing room
facilities will be provided except in the smallest plants.
(8) Signs will be provided designating hazardous areas and non-potable water taps.
(9) Flood lights will be provided for night-time inspection and maintenance.
(10) Crowding of equipment will be avoided around pumps, screens and vacuum filters. Valves and other
operating devices must be readily accessible to avoid injury and encourage proper use so that spillage will