Air conditioning inspection procedure

[edit] Introduction

The summer of 2013 was by British standards warm and the gentle whirr of air conditioning units was a familiar sound, but how many of those systems were operating efficiently and how many have received their mandatory inspection carried out by an accredited inspector.

[edit] What is an air conditioning inspection?

A question that many have been asking in the last few years and if complying is really necessary? 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. Failure to comply could result in a fine.

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% (compared to 80% for display energy certificates and 70-75% for energy performance certificates). To drive a rapid increase in the levels of compliance the government will need to provide either incentives for building owners (or in some cases tenants), or introduce some stiffer sanctions for non-compliant system operators.

[edit] What does the inspection cover?

For the purpose of inspections, air conditioning systems are categorised as either simple or complex. Simple systems consist of split systems or simple heat pumps while complex systems consist of one, or a combination of the following elements:

• Chilled water circuits.
• Fan coil units.
• Chilled beams.
• Air handling units.
• Roof top units.

During the course of 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 complete 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 different 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 capacities / existing loads.
• Time schedules.

[edit] What is the purpose of the air conditioning inspection?

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 heating ventilation and air conditioning (HVAC) systems and that they are operated and managed efficiently. The reward for this exercise is a 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 inspections that BSRIA conducted on a three storey building in Swindon with a total area of 1,200 m2.

The HVAC system in the building was complex and controlled by a building management system (BMS), however after a thorough inspection of the control system it was discovered that the variable air volume (VAV) units were only controlled by local controllers accessible to staff and were causing simultaneous cooling and heating in the same rooms.The improvement to the control system suggested by BSRIA prevented this conflict and has seen a reduction in energy usage.

Another problem identified was the F-gas register in which frequencies of leak pressure tests were only based on the pre-planned maintenance regime and did not reflect the requirement based on the weight of refrigerant. The improvement to the F-gas inspection ensured they were complying with the regulations.

[edit] What happens after an AC inspection is completed?

All air conditioning inspections are logged on the government landmark website from which a copy of the inspection certificate and inspection report can be downloaded by the air conditioning inspector for the building owners.

The information informs the building owners about the following:

1. Cooling capacity of the equipment to inform future retrofitting projects.
2. Remedial work highlighted by the inspection.
3. Updates required to O&M, design documents, F gas register.
4. Other potential follow on projects to consider to maximise the benefit of the A/C inspection such as:
   • More in-depth energy studies of the system leading to continuous commissioning work for system optimisation which results in a greater reduction of energy consumption and running costs.
   • Benchmarking exercises based on the findings to help compare the building consumption with other buildings.

[edit] How did your air conditioning unit cope with the hot weather?

Building owners would not be able to answer the above question without properly asking the following questions:

• Is my air conditioning equipment correctly sized for the heat load in my building?
• Has my equipment been commissioned properly and have my staff been instructed how to control it properly; and do they have enough documented information to manage it in the future?
• Has my existing equipment been serviced properly to avoid possible breakdown during hot weather?

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

This article originally appeared in the February 2014 edition of BSRIA’s Delta T magazine. It has been posted here by --BSRIA 09:42, 5 December 2014 (UTC)

It was written Salim Dermachi, a qualified Air Conditioning inspector working within BSRIA’s sustainable construction group.

[edit] Related articles on Designing Buildings Wiki

• Africa tops world AC growth forecasts.
• Air conditioning.
• Air conditioning inspection (re Energy Performance of Buildings (England and Wales) Regulations)
• Air handling units
• BSRIA.
• Building management system.
• Chilled beams
• Chiller unit.
• Fan coil units.
• HVAC.
• R22 phase out.
• Refrigerants.
• Variable air volume.

Comments

The health of A/C depends on timely and regular maintenance. Timely checkup and maintenance can increase life and performance and can also save some money.