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UTILITY WEEK | 10TH - 16TH FEBRUARY 2017 | 23 Operations & Assets Market view S ub-metering is oen considered to be a relatively small part of a multi-let new build/redevelopment project. As a result, it is usually addressed at a later stage as part of the wider electrical and mechani- cal systems and is not given the attention it deserves. From an operational perspective, meter- ing forms a critical element of the internal systems required for a property to run effec- tively. Without access to data relating to the quantity and distribution of energy usage across a site, it is not possible to manage and minimise energy usage, nor accurately re-charge tenants for their energy consump- tion. Failed or inadequate metering systems present property managers with a number risks, not least the impact this has on cash flow when there is an inability to recover the costs paid out for energy from tenants. Due to the importance metering has on operations, it is necessary to take a com- prehensive and joined-up approach, which needs to start at design stage and be fol- lowed through to commissioning and build- ing completion. Input needs to be given from all the stakeholders throughout the process. Getting the metering design, installation and commissioning right prior to practical com- pletion saves unnecessary cost and hassle further down the line. We have witnessed several projects where the metering has been nothing short of a disaster, with remedial works required oen costing more than the original system. The issues we have encountered cover the com- plete spectrum from the use of incorrect types of meters, to installation issues result- ing in meters recording inaccurately, through to a complete lack of system commissioning. One example is a new-build, mixed use, multi-occupied property we surveyed in the West End of London. It would not have been equitable to recharge electricity, heat- ing, cooling and water costs proportional to the square footage occupied because of the different operating hours and loads placed on the system by the occupiers. Therefore, an extensive metering system was installed comprising electrical, heating, cooling and water sub-meters. However, upon inspec- tion, more than 80 per cent of the mechani- cal meters had problems, including oversized meters which were under recording, meters installed at the incorrect orientation to be able to record accurately, and a lack of com- missioning of heat meters, meaning temper- ature probes and flow parts were located in the wrong pipes. The remedial work under- taken to get the system to a standard where it could be used for accurate tenant billing and management of energy in this com- plex building cost more than £200,000 and included several meter replacements. Getting it right To deliver a robust and reliable metering system that avoids these problems requires many considered steps to be taken. First, metering must be treated as a spe- cialist system in its own right, and not just an add-on to electrical and mechanical sys- tems. Metering needs its own design, speci- fication and commissioning specialist to give it the attention it deserves. It also needs to be recognised that while electrical and mechan- ical designers and installers are good at what they do, they are not generally specialists in metering. Engaging with a metering special- ist for the project is paramount. Furthermore, consideration needs to be given to metering throughout every stage of the project, including design. At design stage, the strategy developed must be informed by the objectives of the building stakeholders, which can established only be by engaging with them. Building regulations set a minimum standard; simply ticking the compliance box does not always address the other common objectives of metering such as tenant billing, participation in incentive schemes and energy reporting. Each meter- ing strategy should be tailored to the spe- cific requirements of the project. Cutting and pasting from one specification to another will guarantee that things are missed, or result in a list of requirements that are not compatible with one another. Ahead of installation, consideration also needs be given to the type of meters required. The assessment must include factors such as the registers from which you wish to record the data, whether MID approval is required, the size of the supply and location. While cost is a factor, this should not be at the expense of addressing what is required. Going for the cheapest option oen ends up being the most expensive option in the long run because meters end up being replaced. Heat meters are expensive in comparison to other meters. We have witnessed numer- ous occasions where the cheapest heat meter option has been sought, which entails pur- chasing a standard low accuracy water meter as the flow part and bolting this together with a heat meter calculator. However, this solution can result in issues with compatibility between meters and data accuracy problems and consequently nearly always ends up with the meters being aban- doned or replaced. The introduction of the Heat Network (Metering and Billing) Regula- tions in 2015 means that where heat meters exist in multi-let buildings with communal heating and cooling systems (or for dis- trict systems), there is a legal requirement to maintain them and use them for billing. Abandonment is therefore no longer possible and the only option is to spend out on reme- dial works to get the meters up to scratch. Having selected the right meters to be installed in the right positions, the final piece in the jigsaw is to ensure their cor- rect installation and commissioning so the meters record accurately. Until recently, many metering systems saw no commis- sioning at all and issues were identified only once the system was in use. You would not install a heating system, cooling system or fresh air system without full commissioning, and the same needs to be true of metering. A best practice approach to metering incorporates all relevant stakeholders' views and includes regular reviews and updates as required throughout the project lifecycle. This will result in a system that meets the needs of building stakeholders once the site is operational. Joanne Merry, technical director, Carbon2018 Give metering its due In a new-build or redevelopment, metering and sub-metering are often considered as just an add-on. Joanne Merry says this is a mistake and can lead to costly remedial works being required later.