Strict adherence to the routines for testing fire alarm systems is crucial to the secure servicing of intelligent building controls. Robin Edmunds takes a look at the maintenance requirements.
The sophistication of today's intelligent electronic systems can be measured by the frequency of maintenance. For example, the maintenance of a motor car once required an 8000 km service which then became 16 000 km, and can now be 32 000 km, thanks to interrogative diagnostic modern electronics.

In this regard, intelligent addressable fire detectors, notwithstanding the fact that they are interrogated for malfunction around-the-clock by the fire control panel, require scheduled maintenance to ensure ongoing operational integrity.

Systematic checking

In the UK, the code for the maintenance of fire detection devices is currently described in BS 5839. This code is in the process of being redrafted to take account of the rapid advances in fire detection development.

Two types of systems are catered for, those with manual actuating devices only (the minority), and automatic fire detection systems (the majority). Of these, intelligent fire detection systems now represent approximately 50%, by value, of all of the new systems installed worldwide.

The responsibilities for servicing are detailed in Section 4, paragraph 29 of the code and can be summarised as follows:

  • correct servicing is essential and, therefore, an agreement should be made with a responsible organisation for regular servicing which conforms to the practices recognised by Loss Prevention Standard LPS 1014 accreditation;

  • the routine to be adopted in individual premises may vary depending upon the use of the premises; equipment installed in corrosive or dirty conditions will need to be checked more thoroughly, and at more frequent intervals than that in clean and dry conditions;

  • the user should check the fire alarm control panel on a daily basis to ensure that it is operating normally, and any faults indicated should be recorded in a log book in order that any remedial action can be taken;

  • on a weekly basis at least one detector or callpoint on one zone should be operated to test the system and to sound the alarm or any other warning devices.

    For systems having 13 zones, or less, each zone should be tested consecutively. The intention is that the interval between tests on one zone does not exceed 13 weeks, or one-quarter of the year, and helps spread the burden of the testing over the year.

    Installation considerations

    A quarterly inspection and test schedule is also required. At this time the log book should be reviewed and control panel batteries and their connections should be examined and tested as specified by the supplier. The alarm functions of the control equipment should be checked by the operation of a detector or a callpoint, as above, and, in addition, a visual inspection should be made to check whether structural or occupancy changes have affected the requirements for siting of manual callpoints, detectors and sounders. The visual inspection should also confirm that a clear space of at least 750 mm is preserved in all directions below every detector.

    Testing procedures

    On an annual basis, a complete systematic test should be undertaken, including all of the above items, together with every detector being checked for correct operation in accordance with all the recommendations of the manufacturer.

    With respect to fire detectors, it is essential that routine tests are adequate to ensure that the required sensitivity to fire is maintained and users should totally satisfy themselves on this point.

    Furthermore, if it is found that the sensitivity of detectors is adversely affected by the rapid accumulation of dirt, then arrangements should be made to increase the frequency of the inspections. Any detectors which have shown continued signs of instability should be immediately replaced.

    Precautionary testing

    Heat detectors should be given a careful visual examination for damage or other conditions, such as a build up of dirt or any coat of paint, likely to interfere with correct operation. Routine tests of operation should be carried out as recommended by the manufacturer, with at least 2% of the installed heat detectors operated annually by application of a suitable heat source as a check on reliability. If it is possible, different detectors should be tested each year.

    Detectors other than heat detectors should be checked for correct operation and sensitivity in accordance with the recommendations made by the manufacturer.

    The current state of development

    As this summary indicates, the maintenance of fire detectors requires a thorough and systematic approach. Professional heat and smoke testing and maintenance equipment is essential and is available from most reputable manufacturers.

    Due to recent technological advances, the most frequently selected fire detectors used for intelligent building controls are now analogue/addressable sensors. In addition to indicating the precise location of the sensor, these models also transmit the condition of the sensing element and, in particular, whether it is operating within the limits specified by the manufacturer.

    The main advantage of this development is that the maintenance schedule of these sensors is pre-planned, taking account of the possibility of accumulated build-up of dust and dirt, so that the integrity of the system is never compromised.

    A further significant innovation has been the design of removable and replaceable chambers for photoelectric smoke detectors, thus extending the useful life of sensors. Such advances permit rapid and low cost replacement of soiled or dirty insect screens without involving any time consuming or costly recalibration.

    Most reputable manufacturers of portable heat and smoke test and maintenance equipment are members of the British Fire Protection Systems Association, and support its aims for the regularisation of best practice procedures. So should you if you don't want to get burnt.

    Worst case scenarios

    The cost of bad fire maintenance procedures is measurable. UK-wide, 38% of unwanted fire calls from false alarms are due to automatic fire systems malfunctioning. In this category, one county fire brigade alone reports some 8% false callouts in the last nine months due to engineers’ incorrect testing and poor maintenance routines. The expenditure in the UK by the Fire Service which is attributable directly to fires is over £1000 million per year which suggests that the elimination by 8% of engineers’ false alarms while testing could yield a saving of approximately £16 million to the public purse. Behind these figures lurk some bizarre practices and oversights:
    • decorators using rubber gloves as dust covers for point type detectors and forgetting to remove them;
    • spider cobwebs enveloping detectors in the roof space over many years;
    • burn-marks on detector housings reveal that tests have been carried out with naked flames at incorrect temperatures;
    • hot air paint strippers have been used to test detectors at incorrect temperatures;
    • insect nests inside detectors obscuring the sensing head;
    • failure to remove factory-supplied maintenance covers from detector housings resulting in non-detection of fire and the building being gutted.

    Whats new in inspection and testing

    Martindale has introduced the IN series of insulation testers offering fast, accurate 16th edition continuity testing. All models have a latching mechanism for hands free use, leads, an automatic zero adjust feature and there is a choice of single or triple insulation test voltages. Prices start from £149.

    PSP Electronics

    PSP Electronics now offers a comprehensive range of patch cords and test leads for electronic test and measurement equipment. Manufactured by Pomona Electronics, they are available with terminations such as stacking or retractable sheath banana plugs, pincers, crocodile clips, spade lugs and grabbers in micro, mini, maxi or smd styles. The range is available in ten different colours. Lengths range from 10 cm to 152 cm.

    Chauvin Arnoux

    The Chauvin Arnoux CA601 digital rms current recorder clamp automatically adapts its measuring range and acquisition frequency to optimise the entire recording phase. Able to monitor current against time continuously over any chosen period, instead of displaying readings data is stored for subsequent downloading onto a pc via RS232 output to create load curve graphs.

    Seaward Electronic

    Seaward Electronic has launched the Combi Compact all-in-one hand held installation tester. Designed to comply with current legislation, the tester can store up to 1500 results in its memory for downloading to a pc, or for printing out directly.

    Newey & Eyre

    Newey & Eyre offers a range of Newlec test instruments including simple power cable locators, digital multimeters, non-rcd tripping digital loop testers and instruments for insulation and continuity testing. All meters are approved to the latest national and international standards.

    AVO

    AVO has introduced the MEGGER Combination Series of hand held instruments which are divided into two test categories. The first range, BMM insulation multimeter, performs tests such as insulation, continuity and all the necessary multimeter functions. The second range, LCB, loop and circuit breaker tester, performs tests such as loop and rcd testing. One pair of testers replaces the functionality of at least five standard instruments.

    • Source

    Electrical and Mechanical Contractor

    Postscript

    Robin Edmunds is the export sales director for Hochiki Europe.