Keeping services plant operational means correct maintenance. With opportunities in this field opening for contractors due to install and maintain contracts, we explain what to do and when.
Building services installations embody a significant proportion of the investment in a building and consequently represent a valuable asset.

The condition and performance of building services deteriorate with time and use. This results in the depreciation of their value and leads to failures resulting in a number of undesirable outcomes:

  • losses due to business disruptions;
  • non-compliance with legal requirements;
  • health and safety problems;
  • depreciation of asset value;
  • increase of costs.
The appraisal of the condition of building services plant and installations requires an assessment of their ability to perform as well as of their physical condition. Functional checks, like the ability of plant to serve the business function, can also be undertaken.

These checks establish the answers to questions such as: 'is the ventilation adequate?'; 'do light levels meet requirements?'; and so on. Functional checks may include monitoring of internal environmental conditions to assess the ability of plant and control equipment to maintain conditions.

Whatever tests are selected, the normal approach is to combine information from a variety of sources:

  • a survey of the external physical condition of the plant and installations;
  • specialist inspections and tests, for example, internal inspections of plant, thermal imaging, acoustic emission testing or vibration analysis, pipe wall thickness testing and so on;
  • data from an assessment of conditions affecting the ability to undertake operation and maintenance, which may impact on longevity of plant and systems;
  • historical problems;
  • knowledge of building owners, maintenance staff and facilities managers.

Information gathered is collated as an information base of property condition and forward maintenance needs/priorities. From identification of forward maintenance needs, estimated future renewal and repair costs can be established for typically 0-5 years and 5-10 years.

Survey approach
The condition survey work is typically split between two teams, one focusing on electrical, and the other on mechanical.

A visual inspection involves examining the outside of all plant, together with internal examination of air handling units and humidifiers, and of main incoming switches and panels, motor control centres and a selection of distribution boards and specialised light fittings.

The plant inspected might comprise:

  • ahus and ventilation distribution system, terminal units and grilles;
  • boilers, primary and secondary circuits;
  • heating system terminal units;
  • chillers, primary and secondary cooling circuits;
  • cooling terminal units;
  • split air conditioning units, dx units;
  • domestic hot water generation and distribution system;
  • cold water services;
  • pumps and the main switchroom;
  • motor control centres;
  • distribution boards;
  • control system, head end and field end;
  • lighting installation and controls;
  • fire and refrigeration systems.

Tests to complement the visual inspection typically include:

  • monitoring of current and power quality on main switch panels over a minimum 24 hour period. This is necessary to provide an indication of any high loading on panels and incidence of power quality problems. These checks are intended to identify potential problems that might lead to power supply failure;
  • spot measurement of current and power quality on selected final sub-circuits – this indicates loading on sample circuits and gives an indication as to whether there are any potential harmonic current/voltage problems;
  • measurement of acoustic emission and/or vibration monitoring from electric motors, pumps and fan casings – this indicates faults in the equipment, particularly on bearings.

Additional tests are selected where the client feels that there is a particular problem to be investigated.

Thermal imaging is recommended to identify equipment operating at temperatures higher than expected. Areas that this is recommended for includes:

  • main switch panels;
  • motor control centres;
  • electric motors;
  • fridge seals and insulation;
  • insulation completeness on pipework;
  • heat/cooling output from radiators, chilled ceilings and floor heating;
  • insulation of the building fabric.

Further tests include:

  • establishing pipework wall thickness – recommended in ageing pipes. This is advisable for pipes close to pumps, where erosion/corrosion may be present and also for pipework likely to attract scale;
  • magnetic field surveys establish the cause of 'jitter' or 'wobble' that affects the picture on VDUs – generally the result of close proximity to power cables;
  • monitoring of the internal environment will also prove the suitability of systems.

Poor internal environment is an obvious indication that plant is not performing as expected. Parameters measured include light level, temperature, relative humidity, CO2 level. Monitoring can also include checking for pollutants eg ozone, particulates and CO. Testing will include occupant questionnaires.

Further testing may also include:

  • building control system checks to establish correct and efficient operation;
  • energy and water consumption surveys and recommendations for reducing usage.
    These can be carried out to establish if energy use is higher than expected and to find opportunities for reduction;
  • air leakage tests establish the building air tightness (building air tightness checks are required for all new commercial buildings over 1000 m2 in the revised Part L2 of the Building Regulations).

The condition survey will also involve examination of existing maintenance records and discussions with staff.

Data collection
The information associated with the condition of installations falls into two categories: core data about the installations eg asset identity, description, age and location; and condition data.

Condition data should include:

  • current condition;
  • whether a defective condition exists;
  • defects or non-conformity to the acceptable condition grade;
  • maintenance action required;
  • existing equipment lists can be used to check off each plant item. In this way a complete record can be kept.

This is supplemented with:

  • method of inspection/data collection (including details of techniques used);
  • any limitation associated with the survey/inspection, eg where plant could not be inspected and reasons;
  • documents inspected;
  • persons interviewed;
  • results of any tests and measurements;
  • photographic or diagrammatic records.

Plant condition data may be ranked as shown in table one, while work can be prioritised as shown in table two.

Expenditure and planning
The principal objective of the condition survey is to establish capital expenditure over future years. Having identified the expected life of plant items and systems, replacement/repair cost estimates can be prepared. A cost limit below which costs are ignored may be applied, eg £3000. This helps to optimise the planning of future maintenance and best utilise the available resources against competing demands. The information derived from condition surveys can also help to:

  • develop a property condition database that can be used for other purposes, such as asset valuations;
  • prepare long-term asset investment plans;
  • achieve a balance between capital and maintenance funds;
  • target scarce maintenance resources;
  • benchmark maintenance expenditure;
  • benchmark property condition.