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On closer inspection

The lack of compliance in building inspections suggests many managers are still not getting on board to reap the benefits. Salim Deramchi of BSRIA goes back to basics

With the flickering of an Indian summer, the cooling season for many has been extended with air conditioning systems still working, but how many of those systems are operating efficiently and how many have received their mandatory inspection carried out by an accredited inspector?

Air conditioning inspections have been a legal requirement under the Energy Performance Building Directive since 2011, for all buildings with air conditioning systems over 12kW total cooling capacity.

Even though this legislation is enforced, the majority of building owners remain non-compliant with the legislation. Figures show that the rates of compliance of Air Conditioning Inspections are at less than 5 per cent, compared to 80 per cent for Display Energy Certificates and 70 to 75 per cent for Energy Performance Certificates.

To drive a rapid increase in the levels of compliance, the government will need to provide either some incentives for building owners – or, in some cases, tenants – to comply with legislation or introduce stiffer sanctions for non-compliant system operators.

For the purpose of the inspections, air conditioning systems are categorised as either simple or complex. Simple systems consist of split systems, multi-system or variable refrigerant volumes; while systems categorised as complex consist of one or a combination of the following elements:

  • Chilled water circuits;
  • Fan coil units;
  • Chilled beams;
  • Air handling units.

During the inspection, the accredited inspector must verify technical documentation including:

  • Asset registers and total cooling capacities;
  • F-gas certificates;
  • Maintenance records of the equipment.

An inspection of the system is undertaken looking at the general condition of the plant including:

  • Air filters;
  • Duct leakage;
  • Refrigerant leaks;
  • Functional performance.

The inspector must review the control strategy and controls integration of equipment, including:

  • Temperature set points;
  • Risk of simultaneous heating and cooling;
  • Unrealised possibilities for free cooling;
  • Time schedules for each system in relation to occupancy patterns.

The system efficiency, sizing and loads must also be assessed by the inspector including:

  • Cooling capabilities and existing loads;
  • Time schedules.

The aim of the air conditioning inspection, as defined by CIBSE Guide TM44, is to ensure that building owners and managers have a good knowledge of their building’s HVAC systems and that they are run and managed efficiently.

The reward for this exercise is reduction in carbon emissions and energy savings.

Although the need to have an inspection may be viewed by many as more red tape for businesses, there are real benefits to be realised, as was demonstrated during a recent inspection that BSRIA conducted on a three-storey building in Swindon.

The HVAC system in the building was complex and controlled by a building management system (BMS), but after a thorough inspection it was discovered that the VAV units were only controlled by local controllers accessible to staff and this was causing simultaneous cooling and heating in the same rooms.

The improvement to the control system suggested by BSRIA resulted in a reduction in energy usage.

After inspection

All air conditioning inspections are logged on the government’s Landmark website (www.hdepcregister.com), from which a copy of the inspection certificate and inspection report can be downloaded by the air conditioning inspector for the building owners.

Air conditioning inspections should not only ensure compliance with legislation but operational benefits such as the reduction in CO2 emissions and energy savings.

Salim Deramchi is senior building services consultant at BSRIA

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