u.s. hydrogen safety standards, guidelines, and practices

U.S. Hydrogen Safety Standards, Guidelines, and Practices

Robert ZaloshProfessor Emeritus

Worcester Polytechnic InstituteWorcester, MA

2HYSAFE SUMMER SCHOOL LECTURE Bob Zalosh, August 24, 2006

U.S. Organizations Generating Hydrogen Safety Codes, Standards, & Guidelines

Consensus Standards Writing

Organizations•ASME

•ASTM

•CGA

•CSA America

•ICC

•NFPA

•SAE

•UL

Authorities Having JurisdictionFederal Government AgenciesState and Local Agencies and BoardsInsurance CompaniesBuilding/Facility Owners


HYDROGEN APPLICATIONS WITH FIRMLY ESTABLISHED FEDERAL

GOVERNMENT SAFETY STANDARDS

Aerospace:

Department of Energy Facilities:

Commercial Nuclear Power Plants:

U.S. Nuclear Regulatory Commission


HYDROGEN APPLICATIONS WITH EVOLVING SAFETY STANDARDS

Hydrogen Fueled Vehicles

Hydrogen Vehicle Refueling Facilities

Stationary Hydrogen Fuel Cell Systems

Onsite Hydrogen Storage

Hydrogen Generated or Used in Manufacturing

Facilities


NRC Requirements for Hydrogen Generated in Accidents Involving

Degraded Reactor Cores

Existing Plants as of 2003

• Maintain hydrogen concentrations below the level that could cause loss of containment if ignited

• Install and maintain reliable H2 detectors

New Plants After 2003

Either

• Inert Containment Building or

• Maintain H2 concentrations < 10 vol % for complete fuel cladding

reaction with water

• Account for local H2 detonations


Size and Strength of Existing Reactor Containment Buildings: 1200 MW Plant


Special Strategies for Different Types of Reactor Containment Buildings

BWR Mark 1 and Mark 2 Containments are

Inerted

BWR Mark 3 and PWT Ice Condenser

Containments Use Deliberate Ignition Devices

PWR Large Dry Containments Use Mixing to

Prevent Detonable H2 Concentrations in Large

Parts of Containment, and Use H2 – O2

Recombiners to gradually remove hydrogen


Deliberate H2 Ignition Via Diesel Engine Glow Plugs Distributed Around

Containment Building


Glow Plug and Heated Coil Surface Temperatures Required to Ignite

Hydrogen – Steam Mixtures


Passive Autocatalytic H2-O2 Recombiner

Used Extensively in French

and German Nuclear Plants

Starting to be used in a few

U.S. PWR Large Dry

Containment Buildings


Hydrogen Fueled Vehicle Safety Standards

1. Fuel Tank Standards:CSA America HGV4SAE J 2579ISO 15869

2. Pressure Relief Device (PRD) Standard: CSA PRD1

3. Vehicle Fuel Cell Systems:SAE J 2579UL 2267 for fuel cell powered industrial lift trucks

4. National Highway Traffic Safety Administration is currently developing a H2 fuel system standard


Four Types of H2 Vehicle Fuel Tanks: Rated for 350 to 700 bar

Type 4: Composite with non-metallic liner

Type 1: Metal (intact after crash)

Type 3: Fully wrapped composite with thin metal liner

Type 2: Hoop-wrapped composite (fiber + resin) with thick metal liner


Some Fuel Tank Requirements in Standards

Ratio of Burst Pressure to Working Pressure : 2.25 to 2.45 for new tanks, depending on standard and type of tank.Ratio of Max Fill Pressure to Working Pressure: typically 1.25 (accounts for compression heating and pressurization during filling)Cycle Life: 5000 to 15000 cycles depending on standard; some standards require cycle counerto be installed.Fire Resistance Test: Must depressurize safely (via PRD) during fire exposure


Tank Undergoing Hydrostatic Pressure Cycling Test

Failure Mode

must be leak

rather than burst


Fuel Tank Maximum Pressure During Fill = 1.25 x Tank Working Pressure

Pressure Settles due to cooling after fill


Burner Length = 165 cm

Hydrogen Tank Bonfire Tests

Test in Tunnel to contain tank fragments if rupture

occurs

Outdoor Test


Hydrogen Jet Flame from PRD Actuation during Tank Fire Exposure

Hydrogen Tank on Left and Gasoline Tank on Right


Tank Failure with Hydrogen Fireball Formation if PRD does not actuate to

vent tank

10 msec 107 msec45 msec


Hydrogen Fireball Rise

997 msec 1240 msec


Type 4 Tank Fragment

14 kg fragment found 82 m east of original tank location


Other Required Tank Tests

Gunfire Test

Drop Test

Type 3 Tank undergoing crush test


Hydrogen Vehicle Fuel Dispensing Standards


NFPA 52 Requirements for H2 Fueling Stations

Documented Hazard Analysis

Hydrogen gas and flame detectors must provide

coverage of all storage, compression, and refueling

equipment.

Either outdoor location or indoor location with one side

predominantly open and roof designed to facilitate

hydrogen venting

Distances for Division 1 and Division 2 hazardous

locations requiring listed electrical equipment

Setback distances to various buildings and roadways


NFPA 52-2006 Requires Fuel Dispensing Connectors to satisfy SAE J 2600 Standard

Lever actuated 3-way valve to allow venting of residual hydrogen via hoseline back

to dispenserSAE J 2601 Communicating Connector


Example of State Guidelines for Fueling Stations

September 2004


Hydrogen Dispenser Safety Features Recommended in California Guidelines


Hydrogen Dispenser with Safety Features


Virtual Refueling Station Code Compliance Web Site

http://www.hydrogensociety.net/VFS3/virtual-hydrogen-

fueling-station.php

Developed and maintained by Canadian Transportation Fuel Cell

Alliance

Allows users to build a virtual refueling station, and determine if it is in

compliance with specific codes and standards.


Standards for Stationary Fuel Cell Systems

New NFPA Hydrogen Technologies Committee will Develop New NFPA 2 Standard


CONCLUDING REMARKSNot to worry if you find the tangled web of U.S. safety codes and standards confusing and frustrating; it will be changing soon anyway.Even if new standards aren’t significantly simpler and more consistent, Web-based tools to access standards and guidelines will facilitate access and understanding.Need more progress in harmonizing U.S. hydrogen standards with European and international standards; requires cooperation from all standards development organizations.

u.s. hydrogen safety standards, guidelines, and practices

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