27/03/2010 by David Slade.

A new compact aspirating detection system has been launched by Hochiki.FireLink NanoFirelink Nano is a single-pipe system with a sampling pipe length for still air of 50m, with either two, six or ten sampling holes, depending on the fire risk. It uses what is termed ‘perceptive artificial intelligence’ which helps ensure that it operates constantly at optimum sensitivity for the particular protected environment. The high degree of sensitivity is achieved by using what Hochiki calls ‘laser-based forward light scattering’ technology.

Remote monitoring of the system at a fire detection and alarm panel, or on a building management system control panel, is made possible by the inclusion of pre-alarm, fire and fault relays, and RS485 communication is built-in for easy networking and remote communication. A Hochiki Enhanced System Protocol compatible APIC – Addressable Protocol Interface Card – is available for addressable systems.

The Nano measures just 185mm wide by 225mm high by 105mm deep, and can be interfaced onto an ESP analogue addressable loop using a Hochiki CHQ-DIM dual input module.

Posted in Hochiki, aspirating fire detection system, Fire detection | No Comments »

28/11/2009 by David Slade.

Premises which combine multiple occupants with sleeping risk are widely acknowledged as requiring particular attention when designing and specifying a fire detection system. The legal definition of a House in Multiple Occupation (HMO) is a complex one, but HMOs include:

-  A building or part of a building occupied by more than one household which shares certain amenities such as a bathroom or kitchen
-  A converted building occupied by more than one household which is partly converted into self-contained flats
-  A building which is made up entirely of self-contained flats that do not meet the 1991 Building Regulation, and where more than one third of the flats are occupied under short-term tenancies.

Such buildings might include residential accommodation for essential workers like nurses, sheltered housing complexes, lodging houses, student accommodation, holiday self-catering apartments, hotels and bed & breakfast premises.

Calls to action
A grim reminder of the consequences of fire has recently been delivered during the inquest into the three deaths in the 2007 fire at the Penhallow Hotel in Newquay. The coroner warned of the risk of further deaths unless there is Government support for hotels and guest houses to invest in fire safety or to ensure compliance with the law.

The first review of the effectiveness in England of the Regulatory Reform (Fire Safety) Order 2005 also widely acknowledged this issue. Broadly speaking, it concludes that fire and rescue services have welcomed the legislation while businesses understand and support the risk assessment principle – where they are aware of the Fire Safety Order’s (FSO) provisions.

This caveat is a crucial one. Only around 60 per cent of businesses are aware of the FSO, and that awareness is particularly low among businesses with fewer than 50 employees. Among this category are many small hotels, guest houses or bed & breakfast premises.

The fire industry and Government have acknowledged that smaller hospitality businesses need to be specifically targeted to get the fire safety message across. The Government, in association with the Chief Fire Officers Association, has produced a booklet called Do You Have Paying Guests? It offers advice to these businesses about the risk assessment procedure and provides a guide to their responsibilities under the FSO.

The hospitality sector itself has raised concerns that many smaller guest houses could go out of business because they cannot afford to upgrade their fire protection. It is therefore clear that, while the political will and public pressure exists to improve fire protection in guest house-type HMOs, there is a need for the fire industry to demonstrate that it can provide a reliable and economical solution.

Understanding HMOs

Unlike larger, more complex buildings, smaller hotels and hospitality premises are relatively simple to navigate and to exit. For example, there may be only one landing, a main staircase and an alternative emergency exit. Fire detection and alarm products for this type of premises, therefore, do not need high levels of sophistication, but they do need to be fit for purpose. It is also advantageous if they offer certain other benefits, such as quick installation and cost competitiveness.

Despite the fact that many HMOs are physically quite simple in layout, the nature of their business means that regulation can be complex. Licensing of HMOs of three storeys or more by the relevant local authority became mandatory as early as April 2006. The idea was to make the general standards of HMOs consistent across the country.

Specific to the fire detection requirements is BS5839, the British Standard for fire detection and fire alarm systems for buildings. The applicable part of the code will depend on the size of the building and the different areas within it. While BS5839 Part 6 is the main code of practice for the installation of fire detection systems within the individual accommodation units of an HMO, Part 1 may also be applicable, particularly in communal areas and larger premises.

BS5839 also divides fire alarm systems into a number of different categories for life protection. They are designated and defined slightly differently within Part 6 (LD systems) and Part 1 (L) systems. At the very least, BS5839 Part 6 recommends that all dwellings be protected to LD3, which means spaces forming part of the escape route within the dwelling, such as the hall, are covered. In newer dwellings or where the risk is high, due to the occupants being elderly or disabled for example, a higher category of LD2 or LD1 may be required. These categories demand more comprehensive cover of communal, living and sleeping areas.

False Alarms
False alarms are another major consideration when developing fire detection products for HMOs. Persistent false alarms can lead to costs for the building owner for inappropriate call-out of emergency services and serious inconvenience for occupants. In extreme cases, it could even lead to occupants ignoring a genuine fire alarm, with potentially fatal consequences.
The most common causes of unwanted alarms are usually a result of tenants’ activities, such as:

-  burnt toast or cooking fumes
-  steam from bathrooms and kitchens
-  aerosols, e.g. hairspray
-  candles
-   tobacco smoke
-   build-up of dust

Other sources of unwanted alarms cannot be attributed to tenant activities and include insects, high humidity, water ingress and other sources of smoke external to the property. Any fire system therefore needs to be able to minimise false alarm incidents while still retaining its ability to raise a genuine alarm.

Another consideration with HMOs is the sequence of events that follow an alarm being raised. In individual dwellings, it may be acceptable for an alarm to be raised immediately so that the family can evacuate straight away, but in an HMO this could cause chaos. It is therefore important to allow the occupants of individual dwellings in an HMO the means of silencing an alarm signal if the source can be dealt with locally (e.g. burning toast) before the entire building is alerted and evacuated.

Posted in BS5839, Fire alarm system - False Alarms, Chief Fire Officers Association, Fire detection, Fire Safety Order 2005, House in Multiple Occupation (HMO), Fire safety | 1 Comment »