Behind the headlines
are high risk because they will accumulate large amounts of grease, so are they required? Attenuators and attenuator pods are also very difficult to clean even with good access. Also, is a 90-degree bend in the ductwork really necessary as that will create a place for grease to accumulate? Radius bends are much safer.
The increasing use of Build- ing Information Modelling (BIM) in the design of building engineering systems means there is a greater appetite for this kind of specific informa- tion because there is more pressure being applied to ensure a system can be designed with maintenance in mind, to minimise risks, but also to help facilities managers keep the whole building run- ning efficiently.
The failure of many buildings to operate as they were designed is a source of general concern across the industry and among property clients – prompted primarily by rising energy costs – but also because of the impact of poor indoor air quality (IAQ) on a building’s fitness for purpose.
TR/19 now has an explicit link with another key piece of B&ES guidance: ‘Specification for Sheet Metal Ductwork’ (DW144), which was also updated this year and provides detailed guidance on how ventilation ductwork should be specified and constructed. That document now also specifically references how ductwork system designers must take ease of maintenance into account. This is largely in response to historic problems of ventila- tion hygiene companies being unable to gain access to systems, or parts of systems, for cleaning because they were poorly designed. BSRIA’s commissioning guidance also makes this link to ensure systems are handed over in a condition that will allow them to be properly and safely maintained.
The research used to pre- pare the new TR/19 provided clear evidence of why ventila- tion needs to be cleaned and revealed the link between residual or impacted dust and microbial activity that contami- nates indoor air with harmful microorganisms. This, clearly, is not good for occupants.
Historically, the TR/19 deposit thickness test (DTT) was used to measure the total accumulation of dust in ducts prior to cleaning and the vacuum test (VT) has been used to validate cleanliness after duct cleaning. However, BS EN 15780 introduced a new preferred vacuum test (PVT) to measure the total amount of dust deposited in a duct. Until now, practitioners using the older DTT testing method have been unable to verify whether they are com- pliant with the BS EN 15780 as neither the standard nor the TR/19 have provided a com- parison of PVT values (mea- sured in grams) and DTT values (measured in microns). The newly updated TR/19 guide has addressed this by including a reference table, which practitioners can use to determine whether a ventila- tion system needs to be cleaned, without undergoing a time-consuming laboratory analysis of the test filters. Also, to determine if a system needs to be cleaned, without the need to wait for laboratory results, practitioners can use the DTT method to more easily check that they are compliant with the re- quirements of BS EN 15780. The internal cleanliness of ventilation systems is vital for human comfort, productivity and health –there is no more basic human right than having good quality air to breathe in your place of work or home. It also influences the overall energy consumption of build- ing engineering systems and their length of operational life. Therefore, a defined, measura- ble level of cleanliness is es- sential and that is what the new TR/19 sets out to deliver. Building owners and their FMs can now have more con- fidence in the way they man- age the safety of their ventilation system because, like water systems, there is now a procedure in place to carry out the required risk as- sessments and ensure their legal obligations are met. Copies of TR19 Edition 2 (2013) and DW/144 Edition 2 (2013) can be purchased at
www.b-espublications.co.uk
The autor is the chairman of the B&ES Ventilation Hygiene group and MD of Indepth Hygiene
For more information on the B&ES and its members, contact Val O’Reilly on 020 7313 4907 or email
val.oreilly@b-es.org
Daily news update at
www.heatingandventilating.net
Comment
RHI can
THIS YEAR HAS seen the expansion of the number of technologies supported by the non-domestic RHI, as well as generous increases to most of the tariffs payable to system owners. And, it seems the Government is much more optimistic about the future, with the Department for Energy and Climate Change (DECC) recently saying it expects to see a marked increase in uptake of the non-domestic RHI following a disappointing first two years. The technologies benefiting from increased tariffs are large biomass heating systems; deep geothermal heating; ground source heat pumps; and solar thermal water heating. New technologies eligible for RHI payments for the first time are air source heat pumps; biomass combined heat and power (CHP); all sizes of on- site anaerobic digestion plant (previously this was limited to under 200kW); and heating from waste combustion. At this moment in time, the
biggest potential market is rural locations off the mains gas grid. Converting the UK’s four million off-grid properties to new technologies like bio- mass, heat pumps and solar thermal, in conjunction with improved insulation, is where we should be looking first. It costs 50 per cent more to heat a building with oil and 100 per cent more with LPG than with natural gas, so a switch to a new technology like biomass can make financial sense. In urban settings, the big oppor- tunity is for air source heat pumps. There is rarely any cost or carbon saving argument for transporting large quantities of biomass into cities. However, low-quality installations are a real threat. And we’re not just talking about ‘cowboys’; even
Jonathan Tedstone boost profits
well-meaning firms have fallen into technical traps and made poor choices over renewable installations. Traditional heating firms cannot simply leap into renewable heating without proper training and a change in mind-set. It must be remembered that
new technologies can only achieve carbon and cost savings if they are appropriate for the building in question, are specified and installed correctly and are used as intended, with the right controls. And no matter which heating solutions are specified, it’s essential to firstly get the fabric of the building right, so that the re- quirement for heat is reduced. There is plenty of business
out there for skilled heating contractors, but projects are not always straightforward. Any firm planning to diversify into this market needs to invest in the right training and seek technical advice from Ofgem, relevant trade associa- tions and manufacturers. For customers to take
advantage of the RHI, the installer needs to be MCS (Microgeneration Certification Scheme) certified and, where applicable, has to work to the specification PAS2030. The technologies themselves also have to be MCS certified for the owners to qualify for RHI payments.
This is an exciting time for
the renewable heating indus- try. Yes, there are complexities and challenges, but with the right training and knowledge there is an enormous market to go after, especially now the non-domestic RHI is even more attractive.
www.baxicommercial.co.uk.
The autor is Jonathan Tedstone, busines project manager at Baxi Commercial
HVR | September 2014 | 17
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