Heating and Ventilating

Dirty ductwork presents a serious fire hazard. But this offers a business opportunity to contractors to educate building maintenance people on their obligations, says Darren Ling
In a recent survey by the Fire Industry Association (FIA) almost 20 per cent of bosses interviewed admitted that due to current economic conditions they had revised some fire safety procedures in an attempt to save money.

This is a risky practice: Precedents have been set whereby those responsible for a building's maintenance have been prosecuted and fined after a fire has been attributed to dirty ductwork. In 2010/2011, the Health and Safety Executive (HSE) prosecuted 551 cases, local authorities prosecuted 129 cases and enforcing authorities issued 18,290 enforcement notices.

The Corporate Manslaughter Act 2007 means it is now a real risk that employers or those deemed responsible will face prosecution resulting in fines or jail should an employee or tenant die where poorly maintained ventilation ductwork or fire safety equipment is deemed a contributing factor. In addition, insurance companies will not pay out on claims if companies are found to be in breach of regulations.

For those responsible for a building's ductwork, maintaining it and ensuring it is working properly is not optional - it is an essential part of building maintenance. HVAC contractors are perfectly positioned to educate building owners and those responsible for a building's maintenance on their health and legal responsibilities and to offer a solution that ensures they remain compliant.

The problem facing 'those responsible' for a building's maintenance, whether it be a school, hospital, office or industrial plant, is twofold. According to reports from the World Health Organisation (WHO):

· Build-up of combustible substances, such as dirt, dust and grease, in air ducts increases the risk of fire and smoke spread.

· Dirty ventilation and air duct systems are the perfect breeding ground for micro-organisms and bacteria that cause illnesses, such as Sick Building Syndrome (SBS).

Preventing the risk of fire - A dirty ventilation duct creates a fire hazard. Dust burns very easily, and with suction in the duct system the fire can spread out to other parts of the building rapidly.

Passive or built-in fire protection (PFP) is probably the most important aspect of fire safety in buildings. UK building regulations require that PFP measures be taken to contain the spread of smoke, heat and flames should a fire occur.

In a building's ventilation system, fire dampers can prevent ductwork conveying fire from one area to another. Heat and smoke travelling down a ventilation system will activate a mechanical stop to release the fire damper shutter, which will contain the fire to its point of origin.

If the shutters are clogged with dirt, dust or other contaminants, fire could spread throughout the building in a matter of minutes. That is why fire damper tests are integral to any fire maintenance regime.

Dangers of dirty ductwork - Ventilation systems provide the perfect breeding ground for potentially harmful bacteria. If not maintained, the accumulation of biological agents from outside the building, including fungal spores and pollen grains, and particles generated indoors, including human skin scales, viruses, paper dust and faecal material from dust mites is unavoidable.

Gases can also be present in our airflow, particularly ozone, commonly found where photocopying takes place, and carbon dioxide. Ozone can irritate the eyes and upper respiratory tract while carbon dioxide causes lethargy, headaches and reduces the attention span of the building's occupants. The build-up of carbon dioxide is typically the result of a lack of airflow around a building, which can be caused by a clogged ventilation system blocked by dust and dirt. It is vitally important to keep ductwork clean in accordance with regulations and standards.

There are a number of regulations and guidelines that building owners must adhere to which contractors need to be aware of when specifying duct cleaning:

British Standard EN 15780:2011 Ventilation for Buildings - Ductwork - Cleanliness of Ventilation Systems is a new standard that clearly defines what is considered acceptably clean in existing ductwork. The standard has newly defined limits set against trigger levels for cleaning these types of systems for existing ductwork which differ from the guidelines set out in the Building & Engineering Services Association's (B&ES, formerly the HVCA) TR/19 guide to internal cleanliness of ventilation systems. The values it recommends for existing ductwork are Low <4.5g/sq m, Medium <3.0g/ sq m and High <0.6g/ sq m, and for recirculation and secondary ductwork it specifies Low <6.0g/ sq m, Medium <4.5g/ sq m and High <3.0g/ sq m.

The Workplace (Health, Safety and Welfare) Regulations 1992 require mechanical ventilation systems to be maintained in an efficient working order and in good repair, including cleaning as appropriate. Regulation 6 states that 'mechanical ventilation systems should be regularly and properly cleaned, tested and maintained to ensure they are kept clean and free from anything that may contaminate the air'.

Health and Safety Guidance Notes HSG202 gives clear guidance to employers about dirty ventilation systems and the effects this can have on staff wellbeing and working environments, and suggests if you find dust by running your finger along the duct opening then it probably needs to be cleaned.

The Control of Substances Hazardous to Health Regulations 1999 place a statutory duty on building owners and operators to control the risk from exposure to materials that may cause harm, such as dust, dirt and bacteria, by way of staff-wide risk assessments and procedures, arduously followed.

The Regulatory Reform (Fire Safety) Order 2005 states that where necessary, in order to safeguard the safety of relevant persons, the 'responsible person' must ensure that the premises and any facilities, equipment and devices provided are subject to a suitable system of maintenance and are kept in efficient working order and in good repair.

The British Standard 9999:2008 Code of Practice for Fire Safety in the Design, Management and Use of Buildings gives recommendations and guidance on the design, management and use of buildings to achieve acceptable levels of fire safety for all people in and around buildings. It recommends that all fire dampers should be tested at regular intervals not exceeding two years, spring operated fire dampers should be tested annually, and fire dampers in dust-laden and similar atmospheres should be tested more frequently.

Armed with these facts, it is easier than it may first appear for hvac contractors to provide the solution for clients responsible for building maintenance. By subcontracting the work to a specialist ductwork cleaning company, contractors will have access to expert advice and services that will help them secure new work now, rather than embarking on lengthy training courses to gain experience.

Specialist ductwork cleaning companies are fully aware of the legal duties facing companies when it comes to their ductwork. More than that, their staff have the qualifications and training to do the job properly and safely.

A qualified ductwork cleaning specialist needs to be trained and certified in confined space cleaning, mobile elevating work platforms, mobile access towers, health and safety, emergency first aid at work, asbestos awareness, general security awareness training, anchor devices, manual handling awareness, fire training, escape breathing and self-contained breathing apparatus and abseiling. A specialist ductwork cleaning company also has the equipment to do the job properly.

// The author is a director of System Hygienics //