1. RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS
Calculations in the Netherlands
By:
ir. Piet Timmers
Ing. Gea Stam
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

2. Contents History and project outline
Calculating Safety Distances for HRS
Results
Conclusions
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

3. History and project outline
2006: ‘Safety distances for hydrogen filling stations’ Matthijsen, Kooi, J. of Loss Prevention in the Process Ind.
2010: ‘Dutch practical guideline’ (NPR 8099)
2015: PGS35: ‘Hydrogen; installations for delivery of hydrogen to road vehicles’.
2014: European Directive for deployment of alternative fuel infrastructure (2014/94/EU) appropriate number of hydrogen refueling points.
2014: “Dutch vision on a Sustainable Fuel Mix”
Intention Dutch Government: >20 public HRS in 2020
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

4. History and project outline
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

5. RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

6. Calculating safety distances for HRS
3rd Party Risk: Risk Based approach.
Rules: “Reference Manual Bevi Risk Assessments”
Location specific risk limit = 10-6 per year
Societal risk: indicative limit: 𝐹 𝑖𝑛𝑑 = 10 −3 𝑁 2
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

7. RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

8. Calculating safety distances for HRS (assumptions)
Calculations based on 1000 kg hydrogen per day
For composite hoses a factor 10 lower failure rate is assumed for scenario ‘breaking of the hose’ (compared to Reference Manual)
2 buffer storages for delivery are present:
one 440 bar (40 kg)
one 950 bar (20 kg)
Probability of direct ignition is 1 for release of gaseous hydrogen
Probability of direct ignition is 0.9 for release of liquid hydrogen
Weather conditions: mean value for the Netherlands
Discussion: Failure probability of automatic ESD:
Reference Manual: probability per use, reaction time 120s
Advisory Board: probability 0.01 per use, reaction time 5s
All calculations done with SAFETI-NL 6.7
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

9. Calculating safety distances for HRS (steps)
Define all scenario’s that are relevant
Reference Manual defines the ‘General failure frequency’
Define relevant factors like fraction per year available or length of pipelines
Calculate the actual failure frequency per year
Calculate the Risk Safety Distances
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

10. Calculating safety distances for HRS (steps)
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

11. Results Type of station Distance to PR 10-6 (m)
Supply of gaseous hydrogen by piping or local production 30 35
Supply of gaseous hydrogen by tube- or cylinder trailer 55
Supply of liquid hydrogen by a tank car. 95
130
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

12. RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

13. Results Type of station Distance to PR 10‑6 Risk determining scenarios
(% that scenario contributes to IR 10-6)
Effect distance (1% lethality)
Supply of gaseous hydrogen by piping or local production
30 m
Intermediate storage (20 kg) at 950 bar – leak (83%)
35 m
Intermediate storage (40 kg) 440 bar – inst release (17%)
Supply of gaseous hydrogen by tube- or cylinder trailer
Tube trailer – fireball as a result of fire in the surrounding (96%)
Supply of liquid hydrogen by a tank car.
Tank car – instantaneous release as a result of external interference (33%)
1200 m
Delivery hose breaks – ESD working (17%)
90 m
Intermediate storage (20 kg) at 950 bar – leak (17%)
Tank car – BLEVE as result of fire in surrounding (13%)
130 m
Results
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

14. Results Type of station Scenario Effect distan ce (m)
Supply of gaseous hydrogen by piping or local production
Intermediate storage (20 kg) at 950 bar – leak 35
Intermediate storage (40 kg) at 440 bar – inst. release 30
Intermediate storage (40 kg) at 440 bar – leak 25
Supply of gaseous hydrogen by tube- or cylinder trailer
Storage (400 kg) at 80 bar – instantaneous release 55
Tube trailer - Fireball
Tube trailer – inst. release
Supply of liquid hydrogen by a tank car.
Tank car – Instantaneous release (weather type F1.5)
1200
Tank car – Instantaneous release (weather type D1.5)
490
Tank car – Instantaneous release (weather type E5)
370
Results
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017

15. Conclusions
safety distances, based on PR 10-6 contour, for a HRS (1000 kg per day), is around 35 m.
However, large effect distance (1200m) for inst. release of tank car liquid hydrogen.
Scenario with large effect distance has low frequency (3.5·10-8 per year) so doesn’t contribute significant to safety distance.
Results are used by Dutch Government for prescription of a fixed set of safety distances for HRS. For supply of liquid hydrogen further research is anticipated.
RISK BASED SAFETYDISTANCES FOR HYDROGEN REFUELING STATIONS | 11 september 2017