Book - School of Science and Technology

680 Running costs. Preventative. Planned procedures are undertaken at regular intervals related tostatistical failure rates of equipment with intent to preserve the life of the plantoverall to a maximum and to minimise the risk of breakdown. Work is carried outto a predetermined schedule enabling resources and material purchase to be plannedin advance.. Conditional. Electrical/vibrational/temperature profiles are monitored on discrete itemsof equipment and compared against models for optimal running conditions. Deviationfrom predetermined parameters indicates the need for maintenance action. This form isbest suited to critical equipment where failure will result in consequential losses.Although there are increased costs associated with sensor installation and analysis,overall cost reduction may be significant in eliminating unnecessary maintenance.LabourAll new plant may be assumed to be fully automatic in normal operation.Below a certain size of plant, the occasional attention required for fully automaticsystems is so small as to be no more than a very part-time occupation, and it cannot begiven a value. What that size is it is difficult to say, as there comes a point, such as in ahospital or a factory, where staff must be employed anyway, even though their duties aremore in the nature of shift technicians or mechanics than involving actual labour. Thecleaning of boilers, etc., keeping plant logs, switching fans and pumps off and on,attending to occasional equipment failure, and minor maintenance jobs, such as oilingand greasing, are still required. For full-time cover this may be worked on a three-shiftbasis which with weekends and holidays involves four men with a possible additional callout,deputising system to deal with emergenciesHowever, if costing must be applied, an assessment can be made at current rates ofremuneration for the kind of attention mentioned above.Contract maintenanceAverage maintenance of small installations is often covered by a maintenance contractinvolving monthly visits costing a nominal sum per annum.In the medium range of installations it is now common practice to employ one of themaintenance contractor firms to include for example checking, cleaning of boilers, lubrication,the cleaning of calorifiers, changing filters on air handling systems, cleaning andchecking operation of air treatment equipment, adjustment and attention to controls andbuilding management systems, inspection and routine activities associated with refrigerationplant and general overhaul. It is often the case that a specialist contractor will beemployed to look after items such as water treatment, controls and refrigeration equipment.Annual charges will vary according to the size of the installation. In the larger scaleplants such as are dealt with by hospital authorities, estate companies and industrialconcerns, the maintenance staff may be part of the organisation, probably operating on aplanned maintenance basis. Building management systems are used for plant asset recordsand in planning, scheduling and recording maintenance activities.Taken by and large, maintenance of building services plant may be expected to becovered by an allowance of the order of £5 £10/m 2 (gross building area) per annum at2000 labour costs. Clearly the cost will depend to a large extent on the level of sophisticationof the systems and the relative ease of access to plant. Reference may be made toindustry maintenance specification guides for further details.