Modern Building Services

MODERN BUILDING SERVICES MARCH 2023 23 FEATURE WORKING BUILDINGS (Passive House) and one choice at a time. The cheapest energy is the energy which we do not use. By improving the insulation, airtightness and heating and cooling sources of our buildings, we will have warmer or cooler and cleaner places in which to live and work. We are also being kinder to the one planet we all share, and Passive House’s exponential growth comes as no surprise. Great design and specifications give us a better-quality building with a smaller carbon footprint. However, whilst designing new build is exciting, wemust accept that over 80%of the buildings which exist today will still exist in 2050 and well beyond. Much of our work is now going to include retrofit and assessing which buildings might have to be demolished and rebuilt, and where retrofits are the better choice. Operational data fromoccupants will not always be available as some of these buildings might not be occupied. Surveys are going to have to be thorough as the more accurate the data you have access to, the sharper your decisions. Retrofits are challenging. But in a resource depleted world and where both operational carbon emissions as well as embodied carbon emissions must be reduced, we need to save as many buildings as possible. We must also look to explore cost effective, regenerative retrofits. Thermal comfort cannot simply be procured in the form of mechanical equipment alone. This is why the notion of ‘electrify everything’ is misleading. If your walls and windows are cold, you are going to lose radiant heat and occupants are going to feel cold. Ten years ago, Allison A Bailes II wrote, “Many architects don’t get it (they will insist that you need more equipment) and the clients don’t get it. And since there is always someone who will talk up the comfort potential of a smart thermostat or radiant floor, it is hard to convince people that it really is about the quality of their wall or window.” To achieve a low carbon, high comfort building for the same price as a conventional retrofit does mean that we must change the way we work. The Portascanner® and the Portascanner® AIRTIGHT can be used as diagnostic instruments to collect critical data in deep retrofits. By conducting regular airtightness checks throughout the build programme, you will know what air permeability values you are achieving and you can approach the pressure test with confidence of a first-time pass. Many deep retrofits sometimes include as many as 8 to 10 air pressure tests, and the leaks are found by a slow and expensive method of elimination. There is now no need for this. Building Health The definition of a healthy building by TheWorld Health Organisation (WHO) is: “A space that supports the physical, psychological, and social health and well-being of people.” Whilst this is true, there is no mention of the health of the actual building itself. Today the value of buildings is intrinsically linked to their energy efficiency and actual building health levels. We all understand the former, but only a few understand the latter. The few that do are those who aspire to close the performance gap and who accept that a high level of airtightness, complemented by either controlled passive or mechanical ventilation, or more likely a hybrid solution, is necessary. Some other benefits of well- ventilated airtight buildings include thermal comfort, acoustic insulation, energy efficiency, pest and infestation control, prevention of water ingress, rot, mould, condensation, and dampness, and importantly achieving fire suppression. Fire prevention in non-occupied buildings, where hypoxic environments can be created and maintained, is becoming relevant too. Since smoke and toxic gases from a fire (which account for most deaths in a fire in a building) have similar sized particles as infectious virus particles, they will follow similar air paths. Fire Doors have a dual purpose. Firstly, as a fire break to stop the spread of flame and to prevent the fire from taking hold, and secondly as a barrier to stop the lethal toxic products of combustion from killing people. We know that temperature has an influence on how smoke and toxic gases infiltrate through gaps and cracks in a building and any gaps or cracks around a Fire Door, particularly in a tall building (or indeed in any other building near to the fire) will permit the lethal products of combustion to flow through the gap or crack and into the air beyond. Some methods of testing Fire Doors for gaps and cracks are unscientific, rudimentary, and inconsistent. It is generally accepted that to provide the required level of fire resistance, all Fire Doors should be reinforced with either intumescent strips or cold smoke seals or a combination of both. More information can be found at www.coltraco.com “...since there is always someone who will talk up the comfort potential of a smart thermostat or radiant floor, it is hard to convince people that it really is about the quality of their wall or window.”