PIPES, VALVES, DUCTWORK AND GRILLES
Components of success
Specifi ers often overlook components such as pipes, ductwork and grilles in HVAC system designs. But doing so can cost them dear, says Jeremy Douglas, project director at Brymec.
A
s pressure mounts on consultants to meet the twin challenges of reducing costs and increasing the energy effi ciency of the systems they design and specify, there is an inevitable temptation for them to focus on big ticket items in a HVAC system that appear to have a greater pay-off than the smaller ‘commodity’-type components. So, for example, when designing large, expensive air movement systems, they might concentrate on the air handling units and fan coil units and dismiss as relatively unimportant components such as pipework, ductwork and grilles.
Although perfectly understandable, this is a mistake because neglecting componentry can adversely aff ect comfort levels in a building and is potentially expensive both in terms of the system’s running costs and the building’s energy effi ciency.
Shrewd building services engineers adopt a system engineering approach to specifying their HVAC systems. A ‘system’ is a collection of diff erent elements that together produce results not obtainable by the elements alone. System engineering involves a systematic eff ort to translate an operational need into system performance and confi guration specifi cations. The best way to achieve this is to call upon
46 October 2017
one company to supply all the components of a ventilation system including pipes, ductwork, valves and grilles. In this way, the specifi er benefi ts from a single source of supply and an integrated system that helps mitigate potential design problems – which could include high room noise levels, poor air distribution and less than satisfactory thermal performance. Service is a crucial element here because these may account for 10% of overall spend, but take 90% of the time.
With a single point of responsibility, a system can be guaranteed, and risk and worry can be eliminated from that area of the project. But systems engineering also off ers another advantage – it enables the designer to fi nd and limit unnecessary costs and avoid over engineering the system.
If the correct pipes, ductwork and grilles are selected on day one to suit the HVAC system, then it saves a lot of time and wasted energy. It also ensures that the installed system works in-line with the specifi cation it was designed to meet.
Pipework
Life in the HVAC pipes and fi ttings sector is far from straightforward as the sector has undergone dramatic change over the last fi ve years largely
because of raw material price fl uctuations. The result is that contractors are far more willing to look for alternative materials such as plastic. Plastic piping used to be specifi ed ‘from the bottom up’, following recommendations from installers. With this in mind, plastic pipe manufacturers have opted to employ specialist teams to increase the awareness of plastic plumbing and off er security in the shape of guarantees.
However, although there has been a gradual switch to the use of plastic pipe in place of copper, most of the plumbing industry still chooses copper piping and fi ttings over plastic. Another trend is the growing use of off -site prefabrication. For most new build projects in London and other large conurbations, road congestion is an issue and there is a shortage of skilled labour. To address this, contractors are moving towards off -site prefabrication which allows transport to take place at off -peak times. This is a development in pipework that we saw in the industrial market, particularly water treatment, at least 20 years ago in the form of prefabricated pump units, dosing plants and treatment units, where pipework was set up in a prefabricated module and dropped into place on the appropriate plant.
This ‘production, not construction’ approach
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