Heating and Ventilating

Malcolm Moss, explains why ductwork needs close attention at every stage of its lifetime in order to provide a safe, healthy and energy efficient indoor environment
IT IS SAFE to say that, in recent years, the ductwork sector has come under great pressure to provide goods and services at sub-economic prices. In fact, failure to do so has resulted in some companies being unable to secure work. The rising cost of materials, combined with market forces, has put the industry in a difficult position.

However, ADCAS believes that now is the time to give the manufacture, supply and installation of ductwork proper consideration because so much rests on thisntechnology in terms of safety, comfort, health and energy efficiency. What's more, we are seeing a rising level of legislation affecting ductwork, which reflects increased recognition of its importance to the effective and energy efficient operation of buildings.

The main areas that clients, specifiers, and building managers, need to think about when considering ductwork are quality of manufacture; standards of installation; ongoing maintenance and life cycle system running costs. Decisions about these factors should not be led by price alone, not least because building owners need to know that their ductwork complies with regulations on safety. Also because poor quality ductwork leads to poor performance of air movement systems in a building and can add to energy costs in the long-term.

There is a host of legislation and guidance on ductwork that specifiers, contractors and building owners need to be familiar with. In general terms, the legislation applies to manufacturing and installation standards; fire safety; and cleaning. Guidance has been produced by ADCAS itself, as well as the B&ES Ductwork Group and other bodies including BSRIA and British Standards.

The ductwork sector has worked hard to ensure that guidance for those in the industry is kept up to date with technologies and techniques. A key example of this is DW144, recognised as the standard specification for ductwork manufacture and installation. ADCAS and the B&ES Ductwork Group have cooperated to produce the most recent update of this internationally-recognised publication, due out in early 2014.

ADCAS also worked to analyse and solve a conflict between the proposed Part L and guidance in DW143 on ductwork leakage and DW144 on pressure classes. As a result, ADCAS and B&ES were able to ensure that it is now easier for ductwork suppliers and installers to meet the legal requirements while adhering to industry best practice.

Another significant development in legislation over the past year has been the Construction Products Regulations (CPR). Since July 2013 it has been mandatory for manufacturers supplying the European construction industry to draw up a declaration of performance and apply a CE marking to their products. This applies to any construction product covered by a 'harmonised European Standard' (hEN), or which conforms to a European Technical Assessment (ETA).

This is certainly an area that requires careful attention from specifiers and building owners alike, since the CPR applies to some types of ductwork but not (currently) others.

ADCAS has issued guidance on this complex area that attempts to clarify the situation.

Currently, smoke extract ductwork must be CE marked to meet the requirements of the CPR. However, fire-rated ductwork does not have to carry a mark yet. This is because BS EN 15781 (Fire resistance tests for service installations - Ducts) has not been finalised and ratified. BS EN 15781 is currently under review by various European countries, including the UK. Once this is ratified, rules on CE marking will change again - another good reason to ensure that ductwork complies with current legislation.

Cleaning of ductwork is vital to ensure a healthy indoor environment. Ductwork poses a challenge because it is often out of sight, and can be overlooked unless a careful maintenance regime is in place. The Europewide standard BS EN 15780 deals with Ventilation for Buildings - Ductwork - Cleanliness of Ventilation Systems. It is a standard that applies in new and existing buildings, and it acknowledges that different types of building have different ductwork cleaning and inspection requirements. Building and facilities managers need to ensure they are very aware of what level of cleaning is required in their properties.

Low occupancy rooms such as storage areas have different rules than, for example, laboratories and hospitals. Within that broad range fall offices and schools. Clearly, in hospitals clean ductwork reduces the likelihood of airborne diseases affecting vulnerable patients. Further, ductwork which is regularly cleaned and maintained is also much more likely to perform as specified in terms of moving air efficiently around a building.

The issue of energy efficiency is especially pertinent, given last year's introduction of the latest update of Part L of the Building Regulations, which deals with energy efficiency of buildings.

Numerous studies have shown that good manufacture and installation of ductwork are crucial. Poorly manufactured and assembled ductwork leads to badly performing ventilation systems, which in turn is a major cause of occupant discomfort. Duct leaks can also cause unwanted noise and lead to unnecessary energy use. As European legislation moves towards the goal of low energy zero-carbon buildings, air tightness will become ever more important. This cannot be achieved with low-quality products or poor installation methods.

So we can see that there are many reasons to pay closer attention to ductwork in buildings. Contractors who only consider price leave their clients open to difficult problems over lack of compliance, as well as higher energy costs and an unhealthy indoor environment. At ADCAS we are constantly surveying our sector to look for improvements. We are at the forefront of developments in guidance and legislation, as well as looking at areas such as making specification documentation more effective.

However, without sufficient profit margin, the ductwork sector cannot invest for the future in this way, or fund technical developments and training. This will not only impact ADCAS members, but also buildings and their owners.

As part of its commitment to providing clear advice on legislation and best practice, ADCAS launches its own website www.adcas.co.uk later this this year. We will be offering the latest news, information and advice which will assist not only our members but the industry as a whole and we will continue to promote the benefits of upholding within manufacturing and installation the highest level of quality.

// Malcolm Moss is President of ADCAS and managing director of Doby Verolec //