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Building Products January 2018

INSULATION AND ACOUSTICS PIPE DOWN Noise from clanking pipes and clattering drainage systems in high rise buildings can become intolerable over time. There are, however, several ways to overcome it, says Luke McMullan, product development manager, Brymec. Plumbing and drainage noise can quickly shift from provoking mild irritation to triggering incandescent rage, particularly in multi-occupancy buildings like maisonettes and apartment blocks. Occupants of these buildings have high expectations for a peaceful life and low tolerance for noisy plumbing systems. Sounds originating in the plumbing system have been amplified in recent years, as more flats are insulated from external noise with double or triple glazing and other improvements to building design. Drainage noise is also becoming more of a problem, as builders rely increasingly on lightweight construction methods. Noise is an invisible problem – out of sight and therefore, often, out of mind. That’s why it is often ignored, or not anticipated in any detail during construction. Indeed, acoustics tends to be at the bottom of the list of priorities in many construction projects. Clients care far more about practicality when it comes to drainage and plumbing. Most are concerned to ensure that it works, doesn’t leak, and offers good water pressure and flow characteristics. But they really need to be more engaged in finding solutions to noise problems. After all, a growing body of research indicates that excess 46 BUILDING PRODUCTS | JANUARY 2018 noise can have a dramatic impact on wellbeing. It causes sleeplessness and therefore tiredness, with a corresponding lack of concentration. It adds to stress and one study even suggests that it can lead to obesity. Although chiefly concerned with noise and vibration control for building services systems, CIBSE Guide B4 Section – 4.3.19 also tackles unwanted noise caused by water flow. It points out that pipes and water flow system components radiate airborne noise. But, noise can also be radiated by building elements such as walls and floors, because these services are structurally attached to them. That’s why CIBSE recommends limiting noise throughout sanitary systems by studying every aspect of the noise chain. This applies not only to appliances, such as pumps and cisterns, but also to pipework. So the type of pipework is important, as is consideration of whether it and the appliances to which it is connected, should be isolated from the building structure. Indeed, pipework can be particularly noisy, with sound travelling through walls in a high rise building. Acoustic insulation, although helpful, is not the complete answer. For example, it won’t cure water hammer (also known as ‘hydraulic shock’), which typically happens when a valve closes suddenly at an end of a pipeline system, and a pressure wave forms in the pipe. This pressure wave can cause major problems – everything from mild noise and vibration to pipe collapse. Noise in water flow systems can be minimised in five ways in particular: • The right choice of pipework, valves, traps etc. • Careful installation to ensure smooth water flow • Avoidance of excessive flow velocities • Noise isolation to prevent the building structure from amplifying sounds • Effective equipment maintenance. Help is available in various publications. For example, Approved Document E – Resistance to the passage of sound, recommends the building gives special attention to workmanship and detailing at the perimeter and wherever a pipe or duct penetrates the floor ‘in order to reduce flanking transmission and to avoid air paths’. It also suggests that pipes and ducts penetrating a floor that separates habitable rooms in different flats should be enclosed for their full height in each flat. The enclosure should be constructed of material with a mass of at least 16kg/m². Meanwhile, EN 14366 – Laboratory


Building Products January 2018
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