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While helping to keep your audience safe with appropriate fire detection, the last thing you want as a theatre manager is to have to evacuate your audience due to an alarm from smoke and fire effects. Robert Jeffreys profiles an installation in Exeter which aims to avoid such a situation.
We’ve all heard the ear splitting ‘boom!’ of the black-powder pyrotechnics fired to simulate the cannon roar of the 1812 Overture or to provide the special effects at a rock concert. Or we’ve jumped out of our seats with the ‘flashbang’ that heralds the entrance of the Demon King at our local pantomime. But how many of us have considered the administrative headaches these smoke clouds and explosions create for theatre fire risk management in their commitment to maintaining systems untroubled by false alarms?
So when the Northcott Theatre, on the Exeter University campus, undertook a major refurbishment recently, they considered these potential problems a top priority and took their concerns to fire system experts for a solution.
As Pete Goodwin, the technical director of Northcott explains: “Theatres are notoriously difficult in respect of detection of unwanted fires or smoke because a lot of productions now regularly use haze machines, smoke generators and occasionally live fire on stage. Therefore the fire alarm system had to have some fairly unique features designed into it to avoid not only the detection of these special effects but also the unnecessary evacuation of audiences.”
At the heart of the Northcott’s new fire alarm and voice evacuation system is the fire detection control panel from Kentec, strategically sited to enable early indication of fire event information. A 4-loop syncro panel with 10A power supply unit was specified, and this interface is supported by a 72-hour standby, together with two display-only repeater panels.
Commenting on the problems of unwanted false interpretations of fire events arising from pyrotechnic and smoke effects on stage, Peter Newman of Alarmtec, the designers and installers of the system, says: “The air sampling did cause us some initial concerns. To avoid this problem, the system has a key-operated disablement time control unit, indicating fire conditions identified within a theatrical programme, with an in-built provision to prevent the accidental switching off of disablements during the controlled period.”
Knock, knock
The design requires that during shows the fire alarm system is switched to ‘double knock’ mode, where cross-zone detection ensures mutual checking between different detectors in different zones, with all cross-referencing detectors triggered in the event of a fire condition. The system sounds a discreet alarm and flashes discreet strobe indicators that the audience cannot hear or see. This gives the house manager a pre-set search and investigation period to discover the cause of the alarm, and then to silence the system or send it to full alert prior to the evacuation of the building.
The timer also has indicators from the ‘front-line’ VESDA (Very Early Smoke Detection Apparatus) air sampling detectors to show whether they are in an alarm condition. Visual indicators that illuminate during a ‘first knock’ condition are fitted at strategic locations in the building.
“The system is specified with an integral override timer,” explains Steve Bonser of Hoare Lea, the M&E consulting engineers appointed by the Northcott to engineer the project and commission it. “This allows the theatre’s technical staff to inhibit its operation during the use of special effects. After the preset time had elapsed the system automatically returns to normal operation; should special effect particulates still be airborne after nearing the end of the preset duration the timer can then be re-initiated.”
Due to the high ceilings in the atrium and stage fly tower areas, careful consideration was given when selecting the type of automatic detection. Point heat detection wouldn’t have operated correctly (or complied with the relevant British Standard) at the required mounting heights or allowed ready, safe access for future maintenance. Instead, an aspirating smoke detection system is used to overcome the maintenance issue and provided improved detection response times.
Emergency announcements
The 6-zone, digital signal processing-controlled routing matrix, handling a voice alarm/public address system rack with hot swappable amps, is custom built to incorporate the theatre’s fire risk strategies. Two zonal firefighter’s microphones with message control are installed at the public entrances, to allow the fire services to make live direct announcements in the event of an emergency.
A zonal paging microphone is also installed in the front of house manager’s office. In addition, the voice evacuation system accepts calls from the stage ‘prompt desk’, which enables the theatre management to use the loudspeakers in the front of house areas to send paging calls to the audience in the bar. The theatre sound engineers can access the system from their patch bay and provide zonal background music as required anywhere in the building.
To achieve a balance between minimising false alarms and providing quick response times to real fires, the system was designed with two modes of operation. A ‘public’ mode is used during theatre performances, when the system is operated in ‘double knock’ configuration. The ‘private’ mode is used outside these times, when the building occupancy is reduced and the system operates in ‘single knock’ mode, providing a faster response to fire. Similarly, the voice evacuation system is designed with these operating modes, so that in the ‘public’ mode, the PA system paging is inhibited in the auditorium and areas opening directly onto it, to prevent any unintentional broadcast disturbing the performance.
The theatre is also provided with a disabled refuge voice communication system, which is interfaced with the fire alarm to prevent operation of the system unless in a fire condition.
As part of the project, building control and fire officers required the whole building to be provided with an automatic fire alarm system to category L1 of BS 5839:2001, to protect both life and property. Commissioning and witnessing of the completed installation was overseen by Hoare Lea and demonstrated to the local fire officer. Although the system specification for this project changed a number of times, the specifiers noted that, because the equipment used is extremely flexible, changes were rapid and straightforward.
Robert Jefferys is Kentec Electronics Ltd’s technical director. For more information contact Kentec on 01322 222121 email robine@kentec.co.uk or visit www.kentec.co.uk
Pyrotechnic safety guide and Code of Practice
Today, special effects wizards tempted to try their hands as pyrotechnicians are urged to read the HSE’s guide Smoke and Vapour Effects used in Entertainment, and the code of practice Pyrotechnic and Smoke Effects published by the Association of British Theatre Technicians.
Clearing and controlling smoke may well be a greater concern than the risk of fire. The Technical Standards for Places of Entertainment says: “Provision should therefore be made to enable the detectors only in the affected area to be isolated in order to avoid false alarms. On no account should it be necessary to isolate the entire system to enable a special effect to be used. Note: The isolation of the detectors should preferably be controlled from the control position for the entertainment. The isolated detectors should also be indicated on the fire alarm control panel. The isolated detectors should automatically return to service after a time lapse sufficient to ensure that any residual fumes have cleared.”
Other modern theatre safety measures include:
– A fire resistant safety curtain has to be tested every day there is a performance.
– Treatments for timber and the use of less flammable fabrics help to reduce ignitability on stage.
– Pyrotechnics come in pre-packed measures and are activated by a low voltage fuse ignition.
– Major effects are set up and controlled by qualified pyrotechnicians, who must have a clear view of every effect.
– Most local authorities require 14 days’ notice of the use of any pyrotechnic effect. Inspection will depend on a risk assessment.
Further information is available from the Association of British Theatre Technicians www.abtt.org.uk
[
While helping to keep your audience safe with appropriate fire detection, the last thing you want as a theatre manager is to have to evacuate your audience due to an alarm from smoke and fire effects. Robert Jeffreys profiles an installation in Exeter which aims to avoid such a situation.
We’ve all heard the ear splitting ‘boom!’ of the black-powder pyrotechnics fired to simulate the cannon roar of the 1812 Overture or to provide the special effects at a rock concert. Or we’ve jumped out of our seats with the ‘flashbang’ that heralds the entrance of the Demon King at our local pantomime. But how many of us have considered the administrative headaches these smoke clouds and explosions create for theatre fire risk management in their commitment to maintaining systems untroubled by false alarms?
So when the Northcott Theatre, on the Exeter University campus, undertook a major refurbishment recently, they considered these potential problems a top priority and took their concerns to fire system experts for a solution.
As Pete Goodwin, the technical director of Northcott explains: "Theatres are notoriously difficult in respect of detection of unwanted fires or smoke because a lot of productions now regularly use haze machines, smoke generators and occasionally live fire on stage. Therefore the fire alarm system had to have some fairly unique features designed into it to avoid not only the detection of these special effects but also the unnecessary evacuation of audiences."
At the heart of the Northcott’s new fire alarm and voice evacuation system is the fire detection control panel from Kentec, strategically sited to enable early indication of fire event information. A 4-loop syncro panel with 10A power supply unit was specified, and this interface is supported by a 72-hour standby, together with two display-only repeater panels.
Commenting on the problems of unwanted false interpretations of fire events arising from pyrotechnic and smoke effects on stage, Peter Newman of Alarmtec, the designers and installers of the system, says: "The air sampling did cause us some initial concerns. To avoid this problem, the system has a key-operated disablement time control unit, indicating fire conditions identified within a theatrical programme, with an in-built provision to prevent the accidental switching off of disablements during the controlled period."
Knock, knock
The design requires that during shows the fire alarm system is switched to ‘double knock’ mode, where cross-zone detection ensures mutual checking between different detectors in different zones, with all cross-referencing detectors triggered in the event of a fire condition. The system sounds a discreet alarm and flashes discreet strobe indicators that the audience cannot hear or see. This gives the house manager a pre-set search and investigation period to discover the cause of the alarm, and then to silence the system or send it to full alert prior to the evacuation of the building.
The timer also has indicators from the ‘front-line’ VESDA (Very Early Smoke Detection Apparatus) air sampling detectors to show whether they are in an alarm condition. Visual indicators that illuminate during a ‘first knock’ condition are fitted at strategic locations in the building.
"The system is specified with an integral override timer," explains Steve Bonser of Hoare Lea, the M&E consulting engineers appointed by the Northcott to engineer the project and commission it. "This allows the theatre’s technical staff to inhibit its operation during the use of special effects. After the preset time had elapsed the system automatically returns to normal operation; should special effect particulates still be airborne after nearing the end of the preset duration the timer can then be re-initiated."
Due to the high ceilings in the atrium and stage fly tower areas, careful consideration was given when selecting the type of automatic detection. Point heat detection wouldn’t have operated correctly (or complied with the relevant British Standard) at the required mounting heights or allowed ready, safe access for future maintenance. Instead, an aspirating smoke detection system is used to overcome the maintenance issue and provided improved detection response times.
Emergency announcements
The 6-zone, digital signal processing-controlled routing matrix, handling a voice alarm/public address system rack with hot swappable amps, is custom built to incorporate the theatre’s fire risk strategies. Two zonal firefighter’s microphones with message control are installed at the public entrances, to allow the fire services to make live direct announcements in the event of an emergency.
A zonal paging microphone is also installed in the front of house manager’s office. In addition, the voice evacuation system accepts calls from the stage ‘prompt desk’, which enables the theatre management to use the loudspeakers in the front of house areas to send paging calls to the audience in the bar. The theatre sound engineers can access the system from their patch bay and provide zonal background music as required anywhere in the building.
To achieve a balance between minimising false alarms and providing quick response times to real fires, the system was designed with two modes of operation. A ‘public’ mode is used during theatre performances, when the system is operated in ‘double knock’ configuration. The ‘private’ mode is used outside these times, when the building occupancy is reduced and the system operates in ‘single knock’ mode, providing a faster response to fire. Similarly, the voice evacuation system is designed with these operating modes, so that in the ‘public’ mode, the PA system paging is inhibited in the auditorium and areas opening directly onto it, to prevent any unintentional broadcast disturbing the performance.
The theatre is also provided with a disabled refuge voice communication system, which is interfaced with the fire alarm to prevent operation of the system unless in a fire condition.
As part of the project, building control and fire officers required the whole building to be provided with an automatic fire alarm system to category L1 of BS 5839:2001, to protect both life and property. Commissioning and witnessing of the completed installation was overseen by Hoare Lea and demonstrated to the local fire officer. Although the system specification for this project changed a number of times, the specifiers noted that, because the equipment used is extremely flexible, changes were rapid and straightforward.
Robert Jefferys is Kentec Electronics Ltd’s technical director. For more information contact Kentec on 01322 222121 email robine@kentec.co.uk or visit www.kentec.co.uk
Pyrotechnic safety guide and Code of Practice
Today, special effects wizards tempted to try their hands as pyrotechnicians are urged to read the HSE’s guide Smoke and Vapour Effects used in Entertainment, and the code of practice Pyrotechnic and Smoke Effects published by the Association of British Theatre Technicians.
Clearing and controlling smoke may well be a greater concern than the risk of fire. The Technical Standards for Places of Entertainment says: "Provision should therefore be made to enable the detectors only in the affected area to be isolated in order to avoid false alarms. On no account should it be necessary to isolate the entire system to enable a special effect to be used. Note: The isolation of the detectors should preferably be controlled from the control position for the entertainment. The isolated detectors should also be indicated on the fire alarm control panel. The isolated detectors should automatically return to service after a time lapse sufficient to ensure that any residual fumes have cleared."
Other modern theatre safety measures include:
– A fire resistant safety curtain has to be tested every day there is a performance.
– Treatments for timber and the use of less flammable fabrics help to reduce ignitability on stage.
– Pyrotechnics come in pre-packed measures and are activated by a low voltage fuse ignition.
– Major effects are set up and controlled by qualified pyrotechnicians, who must have a clear view of every effect.
– Most local authorities require 14 days’ notice of the use of any pyrotechnic effect. Inspection will depend on a risk assessment.
Further information is available from the Association of British Theatre Technicians www.abtt.org.uk