Preventive Maintenance of Single Air Valve

Valves must be accessible and maintained in good operating condition to be able to perform their function of isolation and/or control the flow of water in the pipeline. To facilitate this, it is necessary to know the exact location of each valve and be certain that the valve is in operating condition.

A site inspection should be carried out regularly for the following purpose:

(a)    To check that the location of the valve and surface box are recorded correctly on the locality plan;

(b)    To inspect the valve and surface box for evidence of leakage, damage or displacement.  Check the condition of valve packing or seal, stem, stem nut and gearing;

(c)    Operate the valve to its full open and closed positions, to prevent build-up of tuberculation or other deposits and ensure full valve travel.  A listening rod is useful for ascertaining that the valve is closed;

(d)    Valve chambers are cleaned out and drains freely;

(e)    Record all observations on the Valve Inspection/Maintenance Record on the reverse of the Valve Record card, noting particularly any follow-up maintenance required (e.g. replace packing, repaint, valve stiff, valve box shifted etc.).
Note:  The card is not to be removed from the office, but the information noted and entered on the card later.

(f)    It is desirable that all valves 300 mm diameter and larger, be inspected and exercised at least once a year and others at least once every 3 years.  However, the actual frequency may be varied depending on manpower availability and the relative importance of each valve.

(g)    A summary of inspection and maintenance should be recorded in the Monthly Reports of Water Supply.  (e.g. No. inspected, No. operable, No. not recorded, No. repaired).

(h)    Valves can be identified in the field by painting the number on the body or by attaching a metal or plastic tag.

(i)    Valves replaced or removed from the distribution system should be repaired, repainted, and kept in proper storage for future use.  Even valve requiring major repair, particularly large or expensive valves, can be considered for overhaul.