classic | mobile
Follow us on:
Follow us on Facebook  Share via Twitter  Share via LinkedIn

Hi-Tech Security Solutions Business Directory
Residential Estate Security Handbook 2018

Fire detection for warehouses
September 2017, This Week's Editor's Pick, Fire & Safety, Associations

Following a recent major fire in a Durban warehouse, we deem it necessary to discuss ways in which warehouses need to be protected against fire so that a fire can be detected early and contained before it gets out of hand.

As was experienced in Durban, fires emanating in a warehouse can cause a lot of damage if not contained at an early stage. There is also the environmental pollution that occurs to the surrounding areas due to the large amount of smoke which in a many of cases can be toxic.

Installing a compliant and functional fire detection system for a warehouse requires proper and thorough planning.

The size of the warehouse, activities within the warehouse, being manned or unmanned and available funds will be the major items that will determine what type of system gets to be installed.

Water sprinklers, hydrants and fire extinguishers play a key role in initial fire fighting and are a requirement in nearly all cases, but our key focus is early detection that will enable the exact location of fire to be detected and measures taken to extinguish or contain the fire at an early stage.

The designer of the fire detection system will need to take into consideration the layout of the warehouse and activities that will be happening there during normal working and even after hours. It defeats the purpose to install smoke detectors in a production warehouse where there are fumes or dust produced in fairly large quantities during normal operation, as false alarms will keep occurring.

One must consider the servicing of smoke detectors in heights more than 10 metres, this will require scaffolding or a cherry picker and it may not even be possible to access the smoke detectors in some areas of the warehouse if there are machines or racks that will be installed after installation of the smoke detectors.

Point type smoke detectors cannot be installed in heights of more than 10.5 metres. Some warehouses have openings at the roof sides which allow for natural ventilation and light, some have smoke vents at the roof peak; consideration needs to be taken to ensure that dust and rain will not get into the detection devices installed at roof level.

The probability of stratification of smoke needs to be taken into consideration when siting smoke detectors or any other detectors on the roof.

Stratification occurs in summer when the sun heats the roof sheeting and creates a hot air layer at roof level within the warehouse. During a fire condition, if the hot air layer temperature is greater than the smoke when it reaches this point, the smoke will not be able to penetrate the heat layer and therefore detectors may not function or in the very least the alarm will be seriously delayed.

Fire detection types

It has already been mentioned that standard point type detectors cannot be installed above 10,5 metres, which leaves the fire detection designer only two choices, beam type smoke detectors or aspiration detectors.

Beam detectors are generally well suited for large warehouses due to the flexibility they have in providing coverage for over large areas and heights up to 25 metres. Beam detectors are easily accessible and easier to service than smoke detectors as there will be fewer in number in comparison to smoke detectors and the control unit will usually be installed on the wall of a warehouse as compared to smoke detectors which have to be spread on the entire roof.

Beam detectors need a clear line of sight in order to operate optimally and cannot be installed more than 600 mm from the top of the roof. This is a trap many fire detection companies fall into as in today's roof type structures it is not easy to achieve these two parameters and they end up installing beam detectors further away from the roof and taking a risk that the smoke does not bypass these detectors on the way to the roof.

Beam detectors will also not operate correctly if installed on structures that are prone to movement. Most warehouses are built with iron girders and corrugated iron sheet which expands and contracts as the temperature varies. Installing beam detectors on such structures will affect the operation of a beam detector when the line of sight is lost between the transmitter and receiver.

Aspiration beam smoke detectors is the second option to consider. The ASD (aspirating smoke detector) operates by actively sampling air from a protected area via multiple sampling holes in a pipe network. The air sampled is then transported to the aspirating control panel to detect the presence of smoke. An ASD provides many programmable levels of smoke detection, from a very high sensitivity through to low sensitivity as required. An ASD is approximately 100 times more sensitive than a point smoke detector and it can even detect smoke that is not yet visible to the naked eye.

The ASD is not affected by the roof structure, does not require line of sight and provides better coverage than the beam detector.

Although the initial installed cost of an ASD may be higher than smoke or beam detectors, the ongoing maintenance costs are greatly reduced as the control equipment and filters that require maintenance are installed at eye level and there is no need for high lifting equipment.

  Share via Twitter   Share via LinkedIn      

Further reading:

  • ASIS Security Technology Concepts day
    April 2019, Technews Publishing, This Week's Editor's Pick, Security Services & Risk Management
    ASIS SA kicked the tyres of a few technologies at its first Security Technology Concepts day in February.
  • Visible light facial recognition
    April 2019, ZKTeco, Technews Publishing, This Week's Editor's Pick, Access Control & Identity Management, Integrated Solutions
    ZKTeco recently expanded its reach in the facial recognition market with the launch of its new series of visible light facial recognition (VLFR) products.
  • 2019 Internet of Things (IoT) Barometer
    March 2019, This Week's Editor's Pick, Integrated Solutions, IT infrastructure
    A majority of businesses that use IoT technology agree that it has either disrupted their industry or will do so in the next five years.
  • When cybercrime affects health and safety
    April 2019, This Week's Editor's Pick, Cyber Security
    The threat of a category-one cyber-attack is that everything could seem right – the readings on the meter could be fine, checklists would be followed, and equipment would work – yet danger could still unfold.
  • Cathexis wraps up successful national roadshow
    April 2019, Cathexis Technologies, This Week's Editor's Pick, CCTV, Surveillance & Remote Monitoring, News, Conferences & Events, Training & Education
    Cathexis Technologies successfully concluded its national CathexisVision Roadshow. With events held in Durban, Port Elizabeth, Johannesburg and Cape Town.
  • Milestone Systems launches Milestone Marketplace
    April 2019, Milestone Systems, This Week's Editor's Pick
    Milestone Systems introduces Milestone Marketplace, a digital platform for the video technology industry that connects buyers and sellers to co-create solutions.
  • Biodegradable security seals for SA
    April 2019, TruSeal, This Week's Editor's Pick, Asset Management, EAS, RFID, News, Security Services & Risk Management
    The new TruSeal product extension is produced from a special biodegradable material sourced from Malaysia.
  • CCTV operators’ duties to response personnel at crime scenes
    April 2019, Leaderware, This Week's Editor's Pick, CCTV, Surveillance & Remote Monitoring, Security Services & Risk Management
    Control room operators often have a responsibility to monitor response scenes that go beyond the initial detection and response relationship.
  • Cyber/physical perils in hospitality
    April 2019, Wolfpack Information Risk, This Week's Editor's Pick, Cyber Security, Entertainment and Hospitality (Industry)
    How can we prepare for our holidays and avoid becoming the victim of a scam or data breach?
  • Automatic transmission of fire alarms
    April 2019, FDIA (Fire Detection Installers Association), Fire & Safety
    A quick, automated response to an actual fire alarm can assist in the saving of lives and lessening the extent of damage to property.
  • Surveillance infrastructure has changed
    April 2019, Capsule Technologies, This Week's Editor's Pick, Integrated Solutions, IT infrastructure
    The processing power required to use AI and deep learning is much higher than companies are used to, making it difficult to use off-the-shelf solutions for server and storage.
  • Load shedding calls for essential genset maintenance
    April 2019, Security Services & Risk Management, Fire & Safety
    It is important that such important equipment is maintained properly and serviced regularly in order to be able to cope with extended electricity outages.

Technews Publishing (Pty) Ltd
1st Floor, Stabilitas House
265 Kent Ave, Randburg, 2194
South Africa
Publications by Technews
Dataweek Electronics & Communications Technology
Electronic Buyers Guide (EBG)

Hi-Tech Security Solutions
Hi-Tech Security Business Directory (HSBD)

Motion Control in Southern Africa
Motion Control Buyers’ Guide (MCBG)

South African Instrumentation & Control
South African Instrumentation & Control Buyers’ Guide (IBG)
Terms & conditions of use, including privacy policy
PAIA Manual
    Mobile | Classic

Copyright © Technews Publishing (Pty) Ltd. All rights reserved.