Responding to the Energy Performance of Buildings Directive requirement for inspecting boilers
Published: 17 April, 2006
The potential for boiler inspections to identify inefficient systems and reduce emissions is limited by practical constraints, as ALAN SILVESTER explained to a recent conference.
Included in the Energy Performance of Buildings Directive is a section on the inspection of boilers. This section, Article 8, is aimed at reducing the energy consumption of boilers and their emissions. Like much of this directive, Article 8 provides alternative approaches, which were discussed by Alan Silvester, technical director of the ICOM Energy Association at the recent CIBSE conference on the forthcoming Part L and Part F of the Building Regulations. He also considered ways of meeting the requirements of the directive.
Article 8 defines two approaches to the inspection of boilers. Alan Silvester explained that the industry prefers the approach that requires advice to be provided to users on replacing boilers, modifications to heating systems and on alternative solutions — which may include inspections to assess the efficiency and appropriate size of the boiler (8b). It is notable that the impact of this approach is required to be broadly similar to the much more detailed and prescriptive approach (8a).
That more detailed approach has much to say about the inspection of boilers using oil or solid fuel, but less about gas. While there is a requirement for boilers larger than 100 kW to be inspected, there is no specific requirement for gas-fired boilers less than 100 kW to be inspected at all. As Alan Silvester pointed out, modular plant with an output of more than 100 kW but comprising boilers of less than 100 kW does not seem to be covered at all.
Aside from the technical requirements of the directive, there is the question of who will pay for providing advice and/or inspection. While the Government has made it clear that the consumer will foot the bill, Alan Silvester is concerned about what level of costs will be considered acceptable.
List of ideas
ICOM has devised a list of ideas for small and large systems. They include simple advice, an assessment of energy consumption, assessment of the boiler by a competent person and assessment of the boiler and system by a competent person.
Among ICOM’s early conclusions was that measuring boiler efficiency on site is virtually impossible and that the best that could be achieved was finding the ‘least cost-ineffective option’.
Further consideration suggested that some inspection on larger installations could be cost effective — on the basis that the achievable savings could be greater than for smaller systems. It was also thought that inspection is likely to be more acceptable in the non-domestic sector.
The list of ideas for inspecting boilers and systems in installations greater than 100 kW is designed to identify opportunities for improving the energy efficiency of the system, thereby reducing emissions to the environment and also reducing fuel costs.
Armed with information from manufacturers linking the boiler serial number with its age, it should be a simple matter to identify boilers that are over 15 years old and their efficiency under the requirements of the Boiler Efficiency Directive. Similarly, a discussion with a representative of the client could reveal if a complete examination of a heating system has not been carried out in the last 15 years.
The immediate advice for a client with boilers over 15 years old, a system not thoroughly examined within the last 15 years or an efficiency less than a particular figure would be for a thorough examination of the complete heating system by a competent heating engineer.
Factual information with significant implications for efficiency and emissions that could readily be obtained by a competent person includes the following.
• Is system fully pumped or gravity fed?
• Time and temperature control?
• Night setback?
• Multiple circuits with separate time and temperature control?
• Weather (outside-temperature) compensation?
• Optimised control?
• Do installations with multiple boilers have sequence control?
• Are hot-water pipes insulated?
• Is the supply of domestic hot water separate from space heating?
• Is control provided by a building- management system?
• Is monitoring and targeting incorporated?
For smaller installations, less than 100 kW, the cost-saving potential is thought to be so small that Alan Silvester suggested that the on-cost to an existing visit should be no more than £2. That small amount suggests the filling in of a couple of sheets with tick boxes giving site-specific advice — or an electronic alternative. The scope of the information should include boiler efficiency (from a book or database), advice on annual savings from a boiler change and advice on simple controls and hot water. Advice could also be given on insulating the dwelling.
As a means of increasing boiler efficiency and reducing emissions, the requirement for inspecting boilers in the Energy Performance of Buildings Directive offers great potential. However, as Alan Silvester points out, there are serious practical and commercial constraints. The approach suggested by ICOM is pragmatic and will not incur high costs. Alan Silvester says, ‘We saw no opportunity to make it more perfect than that.’
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