1. New test method for fire suppression systems in
engine compartments of buses and coaches
Jonas Brandt
Project Manager
SP Technical Research Institute of Sweden,
Department of Fire Technology
(jonas.brandt@sp.se)

2. Location of SP

3. Daily in the press

4. Low number of casualties but potential for a catastrophe

5. Fire department call-outs to bus fires in Sweden
The fire department is called out to approx. 0.85 % of all buses every year
0
20
40
60
80
100
120
140
160
2005 2006 2007 2008 2009 2010 2011
Number of bus fire call-outs in Sweden

6. Bus fires – a common issue world wide
• Report from Germany:
• 350 - 400 bus fires is reported every year in
Germany (0.4 % of all buses)
Source: PUBA (2010)
• Report from Finland:
• Bus fires has almost doubled in Finland over the
last 10 years
Source: VTT (2010)
• Report from USA:
• An average of six bus or school bus fires reported
every day in USA
Source: NFPA (2006)

7. Fire source and area of origin
Depending on the survey, the proportion of Engine compartment fires is
between 40 – 75% of all bus fires.
42%
20%
8%
7%
2%
2%
19%
Bus fire area of origin during year 2011 in Sweden
Engine compartment
Wheel well
Auxiliary heater
Electrical fault (different
areas)
Arson (Passenger area)
Welding work (external)
Other/Unknown

8. Situation when fire department arrives
53%
26%
17%
4%
Situation when fire department arrives (Sweden 2011)
Bus on fire
Fire extinguished by driver
and/or automatic
extinguishing system
No fire (self-exinction or
no fire)
Only smoke development
from coolant leakage

9. € 0
€ 10,000
€ 20,000
€ 30,000
€ 40,000
€ 50,000
€ 60,000
2002 2003 2004 2005 2006 2007 2008 2009 2010 2011
Paidinsurancefunds
Year
Automatic fire suppression systems have reduced the costs
Source: Swedish Insurance companies, 2012
Average cost per bus fire for insurance companies in Sweden

10. Fire Suppression Technologies
• More than 15 manufacturers of Fire Suppression systems for bus
and coach engine compartments in the world.
• Different technologies to extinguish engine fires.
• For example:
- Dry Chemical (ABC-powder and BC-powder)
- Wet Chemical (e. g. foam)
- Water mist
- Aerosol
- Clean Agent (gaseous system)
• Are they all good enough?
• How can these systems be validated?
.
•

11. Full scale fire suppression tests

12. Result from the test

13. Some general conclusions after testing fire suppression systems
• It is generally difficult to extinguish engine fires
• The systems works well if they are installed, designed and
maintained in a proper way
• The suppression system must cover the fire hazard areas
• There is a need for quality control procedures to ensure those factors
are controlled

14. The background for SP’s work to develop standards for
fire suppression in buses
• Still high cost for society due to bus fires
• A lack of guidelines and standards to ensure the performance of
installed AFSS – a request from the society (e.g. Swedish Transport
Agency)
• A wish from SP to develop relevant standards which could be used
when making AFSS for buses mandatory

15. • Supported by the Swedish Transport Agency, SP has developed a
new test method (SP Method 4912) to test AFSS for buses and
coaches
• Fire suppression testing according to SP Method 4912
– Must pass tests with different fire scenarios, ventilation level and
obstructions
– Must show a certain re-ignition protection
New test method for AFSS

16. Example of a fire suppression test

17. Proposal for amendment on Reg. 107
• SP Method 4912 is proposed as an amendment of UNECE
Regulation 107. Hopefully to be accepted and voted through at the
GRSG group of UN ECE as well as WP.29.
• Aim: Installation of fire suppression systems in engine compartment
will be mandatory for all new buses (category M2 and M3).

18. Jonas Brandt
Project Manager
SP Technical Research Institute of Sweden,
Department of Fire Technology
(jonas.brandt@sp.se)