Sheltering in buildings from toxic outdoor releases

R. Carrié, R. Goyet, and D. Limoges

CETE Lyon

SETRIC workshop

Mitigation : from experts to local authorities

30 June – 1 July 2005

A concern for local authorities

Risk prevention Urban planning and city code

Preparation to crisis Information to the public Take measures to provide shelter in buildings owned or managed by the

local authority (ex. schools, daycare centres, office buildings, residences, etc.)

Train the public (safety drills) Financial compensations (together with industry and state authority) Share experience with other local authorities concerned

Crisis management Provide shelter in buildings owned or managed by the local authority Temporary transfer of personnel (ex. city police)

After a crisis Learn lessons

Background

Toxic release Chemical, biological, or

radiological contaminants may be accidentally released outdoors near SEVESO industrial sites

Outdoor concentration Determined from risk

assessment For each contaminant,

a perimeter is defined based on health effects

source of pollution

SE L 5 %

S E L 1 %

Objective of shelter-in-place

To protect immediately people from outdoor toxic release for a short time => To maintain a breathable atmosphere in one

interior room Can be active (ex. active pollutant filtration in

mechanical systems) or passive (rely on building airtightness)

Effectiveness of shelter-in-place

Examples : Pensacola, FL – 1977

– Amonia vapour release from railroad tank– 2 deaths, 46 injuries– Breathable and survivable atmosphere was maintained in confined houses

(residents were not harmed) Texas City, TX – 1987

– Hydrogen fluoride release– 3000 people evacuated– 500 treated for burns and respiratory problems– People who stayed in their homes were not injured

Pittsburg, CA – 1998– Chlorine release (400 kg)– 7000 people sheltered in place– 1 employee injured– No injuries offsite

The role of building airtightness

0

50

100

150

200

250

300

350

-0.2 0.0 0.2 0.4 0.6 0.8 1.0

Time (h)

Con

cent

ratio

n (m

g/m

3)

I4 = 0,41 m3/h/m²

I4 = 2,0 m3/h/m²

Outdoor concentration

Irreversible effects threshold

Accompanying measures

To be efficient, shelter-in-place strategy must entail : Information and communication

– Why and how to shelter-in-place Emergency warning systems and safety drills

– Tests of warning systems– Safety drills

Procedures during and after an emergency– Specific procedures (ex. open doors and windows)– Listen to the radio (France Bleue Régions)

Practical experience

School canteen (Salaise sur Sanne, FR)

Primary school (Jarrie, FR)

School canteen

Principal characteristics 1200 m away from phosgene (carbonyl chloride) 1300 m away from amonia 1800 m away from methyl chloride

Objective Provide shelter for 234 persons

Means Identify rooms potentially used as shelters Conduct adaptive measures Control shelter airtightness

Work undertaken Selection of school canteen as shelter among 3 candidates Verification of of airtightness of concrete structure Replacement of exterior doors Verification of ventilation, heating, and electricity systems Emergency shut-off and motorized fire valves Re-designing of pathways to shelter Emergency cabinet with tape, radio, safety flashlights, games, food,

water) Airtightness : n10 < 0.5 Vol/h at 10 Pa

– Measured : 0.4 vol/h at 10 Pa Cost : 75 Euros / m2 (2002) Commissionning : May 2002

Ind ustria l site

Sc ho o l

Prim a ry

Re sid e nc e s

Sc ho o l c a nte e n

Nurse ry Sc ho o l

N

School canteen

School canteen

Procedure Emergency warning sirens Gathering of pupils in shelters Close airlocks Shut off ventilation system and fire valves Listen to the radio Manually tape joints Entertain pupils and wait for end of emergency End of emergency : open airlocks

Primary school

Classroom s Classroom s Classroom s

Speciallybuilt shelter

Speciallybuilt shelter

Speciallybuilt shelter

Industria l site lim it

w indow s w indow s w indow s

Principal characteristics 250 m away from chlorine container Old buildings (1930) not adapted for sheltering

Objective Provide shelter for 315 persons

Means Specially-built shelters to protect both from over-

pressure and toxic release Quality management during construction work

Shelter characteristics 3 reinforced concrete shelters Supply-exhaust ventilation system, with emergency

shut-off and motorized fire valves Airtightness : n10 < 0.4 Vol/h at 10 Pa

– Measured : 0.05 to 0.18 vol/h at 10 Pa Sanitary equipment included Telephone link between shelters Can be used for gymnastics or library (little furniture) Commissioning : October 1994

Primary school

Procedure Emergency warning sirens Gathering of pupils in shelters Close airlocks Shut off ventilation system and fire valves Listen to the radio Entertain pupils and wait for end of emergency End of emergency : open airlocks

The role of local authorities on measures to provide shelter

Call for tenders Define requirements Require that a quality management procedure be implemented

Select main contractor Construction work

If relevant, conduct simulation of shelter-in-place before construction work

The contractor : – proposes technical solutions– carries out the construction work according to the quality procedures

Commissioning Third-party measurements Visual inspections

Conclusion

Sheltering-in-place is an effective measure against outdoor toxic release

If there are requirements on airtightness, quality management should be implemented

The sheltering time cannot be too long Accompanying measures (ex. safety drills)

are essential