1. 4th International Conference on Hydrogen Safety ICHS 2011
4th International Conference on Hydrogen Safety ICHS 2011
September 2011
San Francisco, CA, USA
Hydrogen risk assessment in São Paulo State – Brazil
Newton Pimenta Sandro Tomaz Giuseppe Michelino
198_NevesN

2. São Paulo State (SP) Municipalities: 645 Population:
41 million inhabitants
95% urban
Gross Domestic Product: 34% of the country
21 million vehicles
108,000 industries
GDP
USA: 14.6 tri (1º)
BRA: tri (7º)
FONTES: IBGE, DETRAN-SP

3. SP Environmental Protection Agency (CETESB)
PARA CUMPRIR SUA MISSÃO INSTITUCIONAL, A CETESB DISPÕE DE 34 AGÊNCIAS AMBIENTAIS, AGRUPADAS EM 11 ESCRITÓRIOS REGIONAIS DISTRIBUÍDOS ESTRATEGICAMENTE PELO ESTADO.
TODAS AS UNIDADES REGIONAIS E AS AGÊNCIAS ESTÃO INTERLIGADAS “ON LINE”, PERMITINDO UM ACOMPANHAMENTO PERMANENTE DAS ATIVIDADES DE CONTROLE EXERCIDAS EM TODO O ESTADO.

4. CETESB Main Objectives
Evaluation of environmental quality Air - Water - Soil
Inspection of environmental pollution sources
Technology transfer in the environmental field
Prevention - environmental licensing
Main focus is outside the walls.
Cetesb is more interested in what happens outside the walls of a company than within the walls of the company. Because there are other agencies who deal with occupational health, fire prevention, etc.

5. VILA SOCÓ - CUBATÃO CITY
04/Feb/1984
GASOLINE PIPELINE RUPTURE
FOLLOWED BY FIRE
Source: Banco de Imagens da CETESB/1984

6. 500 victims
93 deaths
Source: Petrobrás

7. Licensing - Prevention
Environmental
Licensing
Previous and
Installation License
Operational License
Risk Analysis
(RA) 7

8. CETESB’s Risk Analysis Flowchart
Hazardous substance and quantity (RD)
Off-site Vulnerability
QRA?
Consequence Analysis
Frequency Analysis
Off-site scenarios selection
Risk estimation (Societal & Individual)
Need risk reduction?
Risk reduction measures
Risk Management Program NO
YES
CETESB’s Risk Analysis Flowchart
YES NO

9. Risk Management Program (RMP)
Process Safety Information
Management of Change
Operating Procedures
Training
Assuring the Quality and Mechanical Integrity of Critical Equipment
Emergency Response and Control
Investigation of Incidents
Audit of Risk Management Systems

10. Comparison: QRA x RMP Quantitative Risk Analysis:
Expensive
Subject to greater uncertainties
Time-consuming
Risk Management Program
Not expensive
Simple
Less time used in analysis
Reference Distance supports the decision-making 12

11. Reference Distance (RD)
Maximum distance reached by 0.1 bar overpressure from vapour cloud explosion (1% death).
Instantaneous release of 20% of the inventory of a vessel/tank
Cloud dispersion to Lower Flammability Limit (LFL)
Vapour Cloud Explosion (VCE)
Software PHAST 6.54 determines the “worst case” consequences for an explosion.
Chart: RD x Mass
consequences were estimated running the PHAST 6.54 software, considering discharge, dispersion and explosion models [9]. The program performs the late (or delayed) explosion modeling at regular intervals during the dispersion of the cloud and finds the conditions which give the greatest downwind effect distance for each overpressure of interest, set in the Explosion Parameters. This is described as the “Worst Case” explosion for that overpressure.

12. Hydrogen RD Chart and VCE
Vapour Cloud Explosion
Hydrogen RD Chart
LFL
Reference Distance (m)
Leak source
Cloud center
Distance to 0.1 bar
Mass (kg)
RD (m) 10 18 50 30
100 38
500 65
1,000 81
1,500 93
10,000
175
100,000
378
Simulation : weather conditions
Parameter
Value
Pasquill Atmospheric Stability D
Wind Speed
2 m/s
Ambient Temperature
25ºC
Relative Humidity
80% 14

13. Risk Management Program (RMP)
RD Application
Population inside
RD circle? NO
Risk Management Program (RMP)
YES
QRA

14. Example of RD Application
Four interconnected hydrogen vessels, each one with 250 kg (total 1,000 kg)
Chart indicates a RD of 81 m
Is there population inside the RD circle? From the figure the answer is YES
Conclusion: the facility must submit a full QRA to CETESB

15. Example of RD Application

16. Discussion
The assumptions may be conservative in some cases. For example: it does not consider any protective system
Initial screening
Covers storage cases
Not for continuous process

17. Conclusion Not the worst case, but conservative
Simple, easy to aplly and cheaper
Money / time saving

18. Thank you! Obrigado! São Paulo Environmental Protection Agency
Brazilian Reference Center
for Hydrogen Energy
Hydrogen Laboratory
at Unicamp
Contacts:
Sandro Tomaz
Giuseppe Michelino
Newton Pimenta