Transcript
Releasing Systems Rob Mennie Senior Consultant Gage-Babcock & Associates Ltd.
Releasing Systems • What is a releasing system? ‣ System designed to detect a fire • Causes release of an extinguishing system in response to the fire
Types of Extinguishing Systems • Releasing systems may control the release of: ‣ Sprinklers • pre-action or deluge, water or foam, water mist
‣ Clean agents • Inergen, Novec, Co2, FM200
Releasing Systems Concept • Three elements: ‣ Input – detection ‣ Process – sequence of operation ‣ Output – notification, annunciation, and release of suppression agents
• Elements are similar to structure of a building fire alarm system, but different in detail
More Harm than Good? • Fire suppression systems sometimes do more damage than fire ‣ Sprinklers spraying computer equipment or valuable artifacts ‣ Frozen piping in cold storage facilities ‣ Foam discharge on aircraft being serviced in hangars
More Harm than Good? • Damage can result from fire suppression operating in absence of fire ‣ Sprinkler heads provide both fire detection and suppression ‣ Physically damaged sprinklers may discharge water as if activated ‣ Damaged piping has the same effect
‣ Even if there is a fire, water may inflict unacceptable damage
The Solution • Separate fire detection and suppression activation ‣ Provide electrical detection of fire ‣ Prevent water release if sprinklers or piping are damaged ‣ Allow for use of systems that do not use water as a suppression agent
Releasing vs. Fire Alarm Systems • Releasing systems: ‣ Use fire alarm equipment and components ‣ Do not meet Building Code requirements for building fire alarm systems ‣ Include functions not found in building fire alarm systems ‣ Provide detection only in limited area covered by associated fire suppression system
Codes and Standards • Fire Alarm System • BCBC CAN/ULC-S524 & CAN/ULC-S537
• Clean Agent Releasing System • no BCBC requirements
• Clean Agent Releasing systems not BCBCregulated nor mentioned in CAN/ULC-S524 ‣ Design is based on good engineering practice
• Installation and verification should follow ULCS524 and ULC-S537 requirements for the systems/components provided
Why Use a Releasing Panel? • Not all building fire alarm panels are listed for releasing • Allows for continuous protection even if the building system is being serviced • Less chance of accidental discharge during inspection of building system
Stand-alone Releasing Panels • Panels must be listed by ULC for releasing • Panels normally protect a single hazard • Panels usually are pre-programmed with some releasing options • Some panels are for pre-action systems and some for clean agent systems
Building Alarm Panels • Most current panels have releasing capabilities • Panel must be listed by ULC for releasing • Panels may protect multiple hazards for single panel • Releasing options normally selectable through panel software
Input – Detection • Automatic detection of a fire is based detection of ‣ heat ‣ Smoke ‣ light from flame
Heat Detection • Heat detection is used where high-heatrelease fires are expected • Types: ‣ Spot-type heat detectors ‣ Linear heat detectors (Protectowire)
Spot-Type Heat Detectors • Spot-type heat detectors are used for area protection where a ceiling exists to bank heat ‣ Ex. Cold storage warehouse with pre-action sprinkler system
Linear Heat Detectors • Linear heat detectors (Protectowire) are used: ‣ for detection near fuel sources that do not have a ceiling to bank heat ‣ where spot-type detectors are difficult to install • Warehouse storage racks • storage freezers • Conveyor galleries
Smoke Detectors • Smoke detectors are used where low-heat release or smoldering fires are expected • Types: ‣ Spot-type smoke detectors ‣ Air aspirating smoke detectors
Spot-Type Smoke Detectors • Spot-type smoke detectors are used for area protection where a ceiling exists and air currents are limited ‣ Small computer or server room ‣ Electrical rooms
Air Aspirating Smoke Detectors • Air aspirating smoke detectors are used: • for high value occupancy where expense is justified • where greater sensitivity is required • where spot-type detectors are difficult to install or service ‣ ‣ ‣ ‣
Large computer rooms Museums Atriums High voltage electrical rooms
Flame Detectors • Flame detectors are used: ‣ for long range detection in large areas ‣ in outside areas where wind may move smoke and heat away from detectors • Petrochemical plants • Aircraft hangars
Manual Detection • Manual detection is used as a backup for automatic detection • It uses dedicated manual pull stations ‣ Manual pull stations are: • clearly labeled for suppression agent releasing • a different color from building pull stations • at exits for egress from hazard area
Process and Output Sequence of Operation • Releasing systems provide more control over response than building fire alarm systems ‣ Response: • is based on a number of detectors or zones detecting fire • may be automatically time-delayed • manually delayed • provides different stages of action
Pre-action Systems • Common types of releasing sequences: ‣ Single interlock ‣ Double interlock
Deluge Systems • Primarily open head sprinklers with solenoid release by single or cross-zoned signal
Process and Output Cross-Zoning • Cross-zoning: ‣ helps reduce unwanted suppression agent discharges ‣ divides detectors into two zones
• Agent does not release unless at least one detector on each of two zones is activated ‣ First zone provides alarm ‣ Second zone provides releasing
Process and Output Automatic Time Delay • Automatic time delay: ‣ provides time for occupants to leave the area ‣ is used where suppression agent may be harmful to human health ‣ provides time for investigation and prevention of unwanted agent release ‣ provides time for ancillary functions • air handling • door closers
Process and Output Manual Time Delay • Manual time delay: ‣ uses an abort switch to prevent agent release while switch is held ‣ provides time for investigation and prevention of unwanted agent release while switch is held ‣ can be a mechanical delay in discharge piping
Process and Output Different Response Stages • Cross-zoning: ‣ allows for escalating response • First zone activation provides notification to start personnel response or evacuation
‣ calls fire department ‣ initiates alarm condition on building fire alarm system • Second zone activation provides different notification signal
‣ releases suppression agent
Interaction with Base Building Fire Alarm System • Releasing system must report: ‣ Alarm ‣ Supervisory ‣ Common Trouble
Additional Operations • Building or Stand-alone systems may: ‣ Operate ancillary functions • Air handling equipment • Process equipment
‣ Shutdown equipment in hazard area ‣ Release motorized dampers to • Seal room for some agents • Pressure relief for Inergen
Notification Devices • Device Types ‣ Alarm bells ‣ Alarm horns ‣ Strobe lights
• Signage ‣ Over exit/entrance doors for hazard area
Common Problems • There are a number of common problems with: ‣ Releasing system panels ‣ Pre-action sprinkler system releasing ‣ Manual switches
Common Problems with Releasing System Panels • Releasing solenoid connected to bell circuit rather than releasing panel ‣ Not listed for such service ‣ No releasing function if bells are by-passed • Releasing function located on building fire alarm panel instead of releasing panel ‣ No suppression agent releasing if building system out of service ‣ Danger of accidental release during servicing
More Common Problems • Releasing system not connected to building fire alarm system ‣ No alarm to other tenants ‣ May not be monitored
Common Problems with Pre-Action Sprinkler Releasing System • Cross-zoned detection ‣ Pre-action sprinklers only release water after system detects fire and sprinkler activates because of heat ‣ If detection is cross-zoned, water will not release until: 1. First zone activates 2. Second zone activates 3. Sprinkler activates ‣ Required cross-zoning exists between electrical detection and sprinkler, not within electrical detection
More Common Problems • Missing detectors ‣ Every space containing a pre-action sprinkler must contain a detector connected to the releasing panel • •
Includes small rooms and closets Without this, no water is released (even if sprinkler operates) because the releasing panel will not activate if no detector exists in protected space
More Common Problems • Abort switch on pre-action sprinkler system ‣ Water will not be released until sprinkler activates ‣ If sprinkler activates, water is immediately required to control fire ‣ Preventing water release is not appropriate
Common Problems with Manual Switches • Manual release pull station same as building pull station ‣ May result in: • accidental release of suppression agent • delayed release if occupants do not understand system operation
More Common Problems with Manual Switches • Abort switch is in isolated location ‣ Unless occupant can reach control panel or communicate with others, he is trapped while pressing abort switch
• Any questions? • Thank you for your attention.
