7th International Fire Sprinkler Conference & Exhibition, Copenhagen, 24-25 June 2008

Protection of Cultural Resources

Sprinkler Protection for Historic Wood churches

Magnus ArvidsonDepartment of Fire Technology

SP Technical Research Institute of Sweden

The objective of the project

Gather relevant fire statistics and examples of illustrative fires or attempts to start fires.

Summarize lessons learned and practical experience from recent fire sprinkler installations.

Identify issues where additional research, testing or development work is needed.

The full report, ”An overview of fire protection of Swedish wooden churches”, SP Report 2006:42 may be downloaded from www.sp.se.

Fire is historically the main reason for damage

During almost 800 years, 1193 – 1984, a total of 524 churches and chapels in Sweden were damaged by fire, war, plundering, collapse, storm, snow, etc.

In total, 447 (85%) were damaged or destroyed by fire.

A total of 106 of these firesoccurred due to lightning.

Examples from recent yearsKatarina church (1990)Rörbäcksnsäs (1992)Salabacke (1993)Lundby (1993)Trönö (1998)Sura old church (1998)Skaga chapel (2000)Bäckaby old church (2000)Södra Råda (2001)Ryssby (2001)Ledsjö (2004)Ramnäs (2006)Älvestad (2007)Öjebyns kyrkstad, Piteå (2007)

Älvestads church March 29, 2007Photo: Johnny Gustavsson

Example: The Södra Råda church (erected c. 1310)

Photos: The Swedish National Heritage Board

Unique and invaluable wall- and ceiling paintings

Highest artistic quality (paintings from 1323 and 1494)

Destroyed in a fire in November 2001

The fire was deliberately started.

System installation case studies in nine churches

Hedareds stave church Frödinge church Älgarås church Habo church Fröskog Skållerud + three additional churches

Objective: Summarise lessons learned and practical experience.

Six of the studied churches (year of installation)

Hedareds Stave Church (2004) Frödinge (2007) Älgarås (2005)

Habo (2006) Fröskog (2006) Skållerud (2006)

The ’typical’ system installation

Water supply: Pump unit and water reservoir positioned in a separate building adjacent to the church.

Complete protection of the interior.

Complete protection inside attics, bell towers and other concealed spaces.

Protection of the exterior. Primarily facades, in some cases also the roof.

Separate buildings house the water supply

Hedareds stave church Habo church

Fröskog church Älgarås church

Water supply equipment

Fröskog church

Habo church Habo church

Fröskog church

Älgarås church (interior)

Habo church (interior)

Frödinge church (attic)

Fire detection systems for facades and roofs

Habo church

Fröskog churchFröskog church

Hedared stave church

Sprinkler protection of facades and roofs

Älgarås church

Sprinkler protection of facades and roofs

Habo church

Sprinkler protection of facades and roofs

Skållerud church

Sprinkler protection of facades and roofs

Photo: Jan G Andersson

Älgarås church

Sprinkler protection of facades and roofs

Habo church

Experiences from the installations Aesthetical aspects important. All installations are impressively

discreet.

The level of system complexity is in some cases high.

The use of antifreeze solutions may be questioned.

Functional tests are essential to discover troubles.

Unintentional activations are quite common.

Unintentional fire alarms are quite common.

Inspection, tests and maintenance are expensive.

Discreet installations

Älgarås church

Habo church

Habo church

Hedareds stave church

The level of system complexity in some cases high

Different systems for interior vs. exterior.

Different system types; wet-pipe with antifreeze, dry-pipe, deluge, etc for different parts of the churches.

Different fire detection techniques; aspirating systems, linear heat detection wires, etc.

New technical solutions, previously not used; gas driven pump units, flushing of piping with compressed air, new nozzle designs, etc.

The level of system complexity in some cases high

The attic of Habo church

Drainage of the system - special solutions.

Y-connections instead of T-connections for pendent nozzles. Compressed air is used to flush the system piping.

Fröskog churchFrödinge church

The use of antifreeze solutions may be questioned

Careless use of antifreeze in Habo church.

Functional tests essential to discover troubles

Several cases documented where systems have failed to operate during functional tests:

1. Pressure drop inside pneumatic pilot line not high enough to open a deluge valve.

2. Component failure in alarm panel = solenoid valve of a pre-action system never opened.

3. Electrical motor protector activated and stopped a pump during fill-up of the system piping.

4. Mechanical problems with the deluge valves.

Unintentional activations quite common

Six cases (totally four churches) of unintentional activations were documented. All cases involved facade protection:

1. Rain water got inside a junction box of the detection system.2. Unknown reason (same church)3. Too low temperature rating of heat detection wire on facade.4. As case 3.5. As case 3.6. Manufacturing defect of a component in the fire alarm panel.

Unintentional fire alarms quite common

Several cases of unintentional activations of fire detection systems have been documented:

1. Water leaking during a hydrostatic test found its way in to a smoke detector. False alarm some weeks later.

2. Leaves were burnt outdoors – activated detection system inside attic space.

3. Too low temperature rating of linear heat detection system installed on facades.

Inspection, tests and maintenance are expensive

Example from Habo church, cost per year:

Own personnel: $5,000 (3 hours / week). Service agreement (the system): $8,250. Service agreement (the power generator): $1,500. Annual, third party inspection: $3,800.

Totally: $18,550+ VAT = $23,200 per year.

Important: Statistics shows that regular inspection, tests and maintenance is the key to high reliability.

Issues where additional research, testing or development work is desired

Water discharge densities and design areas relevant for heritage buildings.

The protection of facades and roofs. Fire detection for facades and roofs. Flashover prevention systems. Water exposure to vulnerable paintings and décor. The use of antifreeze. System reliability. Streaming of water in cold sprinkler piping – the risk for clogging.

Thank you!