Plant & Works Engineering February/March 2023

Focus on: HVAC Energy & Environmental Management February/March 2023 www.pwemag.co.uk Plant & Works Engineering | 31 W ater pumps, ventilation, air conditioning and heat pumps are all essential equipment in many modern buildings, whether industrial or residential. However, all of these types of plant equipment have mechanical elements, which generate vibration. This vibration can be carried round the building via ducts, pipework or parts of the building structure and can be realised as audible noise Historically speaking, much of this equipment is housed in the basement of the building. Nowadays, with space at a premium, that might mean someone living right next to a noisy plant room. Alternatively, this equipment might be placed on the roof of the building, where it is assumed to be out of the way. That might be a great option from an architectural point of view, but it can accentuate the issue of noise pollution. As you go higher up a building, by necessity the structure must be more lightweight. This makes it easier for vibration generated by the equipment to excite and be carried through the structure directly or via service runs where it can manifest as noise. This noise can be both a health issue and a planning consent issue. However, you don’t need to put up with it. Where to start? Ideally, building acoustics should be considered at the design stage. It is often much simpler and more cost effective to address issues at this stage, as opposed to costlier retrofits further along in the life of the building, after complaints start to occur. Unfortunately, acoustics is sometimes considered something of a dark art and vibration control is even more of an esoteric area, so where do you start? The Chartered Institute of Building Services (CIBSE) provides clear guidance on this. Originally developed by specialists in the 1960s and most recently updated in 2016, the CIBSE B4 guidance document offers advice on the generation, prediction, assessment and control of noise and vibration from building services. Unfortunately, the existence of these guidelines and their potential value is relatively unknown. The document summarises some of the main problems that arise from things like HVAC systems and has a special section dedicated to plant rooms. Enforcing these guidelines from the outset would quickly eliminate most of the common problems in new buildings. When things go wrong Where you face a noise or vibration problem in a pre-existing building, the B4 document should still be your first port of call. Despite the availability of this guidance, there are many common problems that result simply from ignorance of the guidelines. Broadly speaking, the two most common issues related to vibration are incorrect choice of isolator or poorly designed product. A common mistake that covers both categories is placing plant equipment on cheap, overly stiff mats or pads in situations where springs or higher deflection elastomeric supports are necessary. The springs may cost a few hundred pounds, whereas the matts might only be a few quid. However, we are often involved in retrofit projects where cheap pads have to be swapped out and spring mounts installed in their place. Add to this the time and cost of consultancy fees, as well as disruption and ire from tenants, and you quickly eliminate any savings. Plus, there is a responsibility to consider the whole life cost of a building, as remedial works also incur a carbon cost. Many of the most common problems are readily solvable, but non-experts put up with them because they think they have no choice and contractors install sub-optimal systems due to lack of oversight or experience. We once worked with a large automotive manufacturer whose plant equipment – specifically a climate chamber with a vacuum pump – was causing vibration in an office as far as 400 yards away. They had called in multiple different companies over a period of years to try and solve the problem before they eventually found us. The final solution was actually quite straight forward. Noise from plant equipment may be something we all put up with, but it shouldn’t be that way. If the industry standards set out in the CIBSE B4 guidance were enforced properly, noise disturbance would be the exception and not the norm. Don’t be afraid to demand more, you deserve that peace and quiet after all! If you need help in following the CIBSE guidelines, visit mason-uk.co.uk Whether we’re in a residential or an industrial setting, we’ve all encountered situations where we’re forced to put up with noise disturbance from a pump, pipe or fan, but should we have to? Adam Fox, director at vibration control specialist Mason UK, explains why simply following the available guidance should eliminate this all-too-common problem. Do we have to put up with vibration from plant equipment?