Maintenance of engineering services plant within buildings has traditionally been carried out in a variety of ways by a variety of people.
Relatively simple engineering services, in small shops and commercial offices, need not be maintained routinely. The assumption is that when a breakdown occurs adequate resources can be called in, such as a utility company or local contractor.
Large organisations such as local authorities may have a formal or informal agreement with local contractors to respond to a breakdown at agreed labour rates. Supervision may be by an individual appointed by the building operator, the property manager or at the discretion of the contractor.
A second option is to make a more formal arrangement for a property with a maintenance contractor. For example, a service and maintenance agreement with the local gas supply company for gas-fired equipment, or regular testing of the electrical installation by an electricity company. Dedicated maintenance contractors will also offer such services.
A third option is to employ a maintenance labour force that routinely inspects and maintains all the engineering services. For building operators with a small-to-medium sized property, the cost cannot usually be justified unless additional tasks, such as portering and message services, are included. The employee may be able to handle routine problems, but would call on specialists when non-routine problems occur.
In larger buildings such as major office complexes, department stores, hospitals and hotels, which can have a variety of plant providing essential services, a more formal maintenance structure tends to be adopted.
Two principal options exist: use of directly employed labour, or a maintenance contractor. (Further information on comparing the different options is available in the Chartered Institution of Building Services Engineers’ (CIBSE) technical memoranda TM17 ‘Building services maintenance management’.)
As the size of building or property estate increases, so does the justification for employing a specialist to take responsibility for maintaining the engineering services. Directly employed labour and maintenance contractors may sub-let work on specialist equipment where they have insufficient expertise.
Types of maintenance
Planned maintenance is organised, controlled and follows a recognisable procedure. It can take several forms, such as:
Preventive maintenance Carried out at predetermined intervals or corresponding to prescribed criteria and intended to reduce the probability of failure.
Corrective maintenance Work done once a fault has occurred to restore plant to normal operation; this approach would be subject to prior agreement by the building user that this is an acceptable basis for maintenance.
Immediate maintenance Necessitated by unforeseen breakdown or damage and needing to be put in hand immediately.
Scheduled maintenance Preventive maintenance carried out to predetermined intervals, number of operations, hours run etc. The Heating and Ventilating Contractors Association (HVCA) in conjunction with CIBSE has published a series of standard maintenance specifications for the majority of building services’ plant and equipment. These provide a useful source of reference for maintenance requirements and typical frequencies.
Opportunity maintenance Work done as and when possible within the limits of operational demand.
Design-out maintenance Other forms of maintenance may be inappropriate, therefore maintenance needs are designed-out to achieve the required level of reliability.
Condition-based maintenance Work initiated by trends highlighted by routine or continuous monitoring of the condition of plant, such as general performance or specific parameters (eg bearing vibration).
Run to failure The consequences are such that plant can be safely and cost effectively run to destruction without serious loss of service. This may assume there is a standby unit that will automatically operate when the duty unit fails.
Whichever maintenance plan is adopted, it is likely to consist of a mixture of these methods. It needs to start with an assessment of what is effective followed by a decision on what is desirable and an assessment of labour, materials and facilities resources. Together, these should provide a rational basis for preparing a programme of planned maintenance.
Condition-based maintenance is initiated by the monitoring of the condition of plant. This is becoming more applicable to building services as techniques gain understanding and credibility, equipment becomes simpler and cheaper, and clients demand more reliable plant.
The idea is that a parameter can be established that gives a good indication of plant condition and also reflects the likely mode of failure. By monitoring this parameter, the required timing and type of maintenance can be determined. Monitoring can be assessed by establishing trends over time to identify marked departures from the norm, or by condition checking where readings are compared with established parameters for the particular item of plant or equipment on a ‘go/no go’ basis.
Various techniques are available, generally requiring routine plant inspections. These include: visual inspections; thermography; oil wear analysis; ferrography, temperature, pressure, speed and flow monitoring; vibration analysis; bearing shock measurement; voltage, current, power and frequency monitoring; and non-destructive testing. Plant that could justify condition monitoring would typically be expensive to maintain, expensive to replace if run to failure or critical to the overall building operation. If failure could lead to high consequential costs, or lead to an unacceptable situation (eg creating a safety hazard), plant could also justify condition monitoring.
‘Designing-out’ may appear an ideal solution but should be considered only where other options are unavailable. For example, where health and safety considerations, operational requirements, reliability demands or even building location dictate that other maintenance requirements are not viable. In most cases it is unlikely to be encountered as the only option, but the client should be aware of it and ensure that this is clearly defined in the design brief if considered appropriate. This may be costly, but is far more readily addressed at the design stage than during or after installation.
A technique increasingly being adopted in the process industry entails relating the operational requirements of specific plant to known or recorded reliability information. This can allow more cost-effective use to be made of maintenance resources, particularly labour. It can be implemented by methodically listing plant items and using analyses carried out by maintenance operatives, supervisors and managers to review and improve the maintenance regime with ongoing monitoring of the results of changes to allow continuing improvement.
Choice of maintenance strategy
A technique being adopted in the process industry entails relating the operational requirements of specific plant to known or recorded reliability information. This can allow better use of maintenance resources.
A building operator needs to determine the most appropriate choice of maintenance procedures when a building is put into full operational use. The strategy may closely follow the original maintenance policy established by the client in conjunction with the designer. But, as the project progresses to completion, other factors may need to be considered. The usage pattern of any functioning building is likely to change and maintenance procedures will need adapting.
For example, in the early years it may be appropriate to keep an installation close to its original condition. But as wear becomes more pronounced, the needs of occupants change and technology improves, there is likely to be increasing demand for refurbishment.
Whichever approach is adopted, it should take account of the future requirements of a building and its services, the current physical performance and functional suitability of plant, proposed changes of use (particularly where they affect plant and services), statutory and legal requirements, and any standards of maintenance specified by the building operator.
To be effective, such a procedure needs to be kept up-to-date; perhaps on a five-yearly basis for a relatively new property with little change of use, but more frequently where services are approaching the end of their economic life or building use is changing frequently.
Main principles of a planned system
A planned maintenance system must include:
- items to be maintained
- maintenance policy appropriate to each item
- labour required
- material resources required
- when and how often the work is to be done
- how the maintenance system will be administered and the results analysed and monitored.
Maintenance services
A direct labour organisation or maintenance contractor may be required to carry out additional services, but in general will offer:
- routine inspection and maintenance of engineering plant
- planned lamp replacement, five-yearly electrical inspection and portable appliance testing
- monitoring of plumbing and water services operation (for legionellosis control)
- inspection and operation of high-voltage electrical installation
- first line response to emergencies and pre-agreed critical alarms
- ensuring compliance with statutory requirements for services installations
- provision and control of on-site engineering stores and purchase and installation of engineering plant and equipment
- energy management by: ensuring efficient plant operation, also purchase, and where appropriate storage, of fuel
- supervision/control of specialist contractors
- inspection, compliance testing and monitoring of fire systems and equipment
Source
The Facilities Business
