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Member questions: Faulty fan-coil, IAQ, obsolete StandardsJuly 2016

Jayne Sunley, Information Manager

Written by Jayne Sunley, Information Manager, BSRIA

Q1. If a faulty 4-pipe fan-coil is being replaced and the valves are remaining in situ what installation process do we need to go through?

A minor replacement or repair to an existing system should ideally be flushed through before connection to the original system but provided that clean materials and components have been used this may be a simple water flush to drain followed by a brief back flush with system water. There is no need for water quality analysis but you need to ensure that the concentrations of the existing treatment chemicals (including biocide) are fully up to spec.

In the case of one replacement fan coil in the original location, most contractors would install and briefly backflush while filling from the system (as per BG 29 section 7.1). There have been some cases where fan coils have been flushed with water on the bench before installation, which might have some benefits, but chemical cleaning should not be necessary. If you’re creating a new branch (however short) then the branch itself should be flushed before opening to the fan coil as there may be residues from the connection process.

Q2. I’ve heard that design parameters for spaces concerning IAQ are categorised as I, II, III and IV. What do these categories mean, and where are they stated?

BS EN 15251:2007 defines the categories. For example, category II is ‘Normal level of expectation and should be used for new buildings and renovations’. A building in this category would be expected to achieve less than 10 percent of persons dissatisfied (PPD) with the thermal environment (a PPD of less than 10 percent), and would have a ventilation rate of 7 litre/s per person.

This doesn’t override Approved Document F, which gives a ventilation rate of 10 litre/s per person for office buildings.

Q3. I’m using a British Standard but when I checked to see whether it’s still current BSI have declared it obsolescent. What does this mean and is it still possible to use it?

The status obsolescent is a bit of a strange one, while it is technically a withdrawn standard it is also still current. BSI recommends that obsolescent standards are not used for new equipment or processes but do state they can still be used to service existing equipment that is unlikely to be replaced.

Q4. What is the convergence between Smart Building Technology and Information Technology?

As the built environment becomes increasingly “smart” and data-driven, the way that buildings are planned, commissioned and operated needs to evolve to keep pace. On the one hand, IT departments, which have traditionally been considered as separate from building and facility management, can add value both in the design and the operation of the building and its systems, especially in areas such as cyber security. On the other, building managers and operators need to become more ‘data literate’, whether at the level of the building manager understanding – at least at a high level - how data can be used to reduce operating costs or improve comfort and performance, or as that of the ‘out of hours’ caretaker who understands how to respond to events and ‘alerts’ generated by the system.


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