What is Lessons Learned?

What is H2LL?

This database is supported by the U.S. Department of Energy. The safety event records have been contributed by a variety of global sources, including industrial, government and academic facilities.

H2LL is a database-driven website intended to facilitate the sharing of lessons learned and other relevant information gained from actual experiences using and working with hydrogen. The database also serves as a voluntary reporting tool for capturing records of events involving either hydrogen or hydrogen-related technologies.

The focus of the database is on characterization of hydrogen-related incidents and near-misses, and ensuing lessons learned from those events. All identifying information, including names of companies or organizations, locations, and the like, is removed to ensure confidentiality and to encourage the unconstrained future reporting of events as they occur.

The intended audience for this website is anyone who is involved in any aspect of hydrogen use. The existing safety event records are mainly focused on laboratory settings that offer valuable insights into the safe use of hydrogen in energy applications and R&D. It is hoped that users will come to this website both to learn valuable lessons from the experiences of others as well as to share information from their own experiences. Improved safety awareness benefits all.

Development of the database has been primarily supported by the U.S. Department of Energy. While every effort is made to verify the accuracy of information contained herein, no guarantee is expressed or implied with respect to the completeness, causal attribution, or suggested remedial measures for avoiding future events of a similar nature. The contents of this database are presented for informational purposes only. Design of any energy system should always be developed in close consultation with safety experts familiar with the particulars of the specific application.

We encourage you to browse through the safety event records on the website and send us your comments and suggestions. We will continue to add new records as they become available.

How does H2LL work?

If you have an incident you would like to include in the H2LL database, please click the "Submit an Incident" button at the top of the page. You will be asked for a wide range of information on your incident. Please enter as much of the information as possible. In order to protect your and your employer's identities, information that may distinguish an incident (your contact information, your company's name, the location of the incident, etc.) will not be displayed in the incident reports on H2LL.

Lessons Learned Corner

Visit the Lessons Learned Corner Archives.

Key themes from the H2Incidents database will be presented in the Lessons Learned Corner. Safety event records will be highlighted to illustrate the relevant lessons learned. Please let us know what you think and what themes you would like to see highlighted in this safety knowledge corner. You can find all the previous topics in the archives.

Summary

A gas-phase explosion in a storage tower with semichemical pulp at a paper mill has possibly been caused by combustion of a mixture of hydrogen and air. The hydrogen was formed by microorganisms in the pulp. Ignition may be due to electric sparks in connection with an electric field in the mist above the pulp.

Accident Description

A gas-phase explosion took place in a 1,300 m3 storage tower for semichemical pulp at a paper mill. The storage tower was 21 m high and equipped with an agitator at the bottom. By a pumping arrangement, the pulp was circulated from the bottom to the top through external pipes connected with the mill (Fig. 1).

On a given day the production was stopped at a time when the storage tower was loaded with 1,000 m3 pulp at a view more

A hydrogen explosion occurred in an Uninterruptible Power Source (UPS) battery room. The explosion blew a 400 ft2 hole in the roof, collapsed numerous walls and ceilings throughout the building, and significantly damaged a large portion of the 50,000 ft2 building. Fortunately, the computer/data center was vacant at the time and there were no injuries.

The facility was formerly a large computer/data center with a battery room and emergency generators. The company vacated the building and moved out the computer equipment; however the battery back-up system was left behind. The ventilation for the battery room appeared to be tied into a hydrogen monitoring system. The hydrogen sensor was in alarm upon emergency responders arriving at the scene (post-explosion). 911 callers view more

Hydrogen was stored in a plant in a 42 ½ ft diameter sphere made of 3/16 inch steel. The sphere was partitioned into two hemispheres by a neoprene diaphragm attached around the equator. Hydrogen was stored under the diaphragm, while the upper hemisphere contained air. An explosion-proof fan was situated in the upper portion of the sphere in order to provide a slight positive pressure on the top of the diaphragm.

When the plant was shut down for a local holiday, the fan on top of the hydrogen sphere was also stopped. During plant startup two days later, a violent explosion occurred in the sphere. The sphere shell was torn into many sections by the explosion, and some of the sections were propelled as far as 1,200 ft. Some of these sections struck flammable liquid storage tanks view more

Hydrogen and chlorine concentrations at a certain plant are measured once each shift. On the morning of the explosion, the hydrogen concentration in the chlorine header leaving the cell bank was 0.47 percent. After passing through the chlorine coolers and liquid/gas separators, the hydrogen concentration of the gas streams increased to 2.5-3.2 percent H2, i.e., 63-80 percent of the lower flammability limit.

About 5 hours after the measurements were made, the DC power to the electrolysis cell bank was shut down because of intermittent power supply problems. At that time, a low-order explosion was heard from the chlorine dryer area of the plant. Thirty seconds later, chlorine gas began escaping from the chlorine header pumps, and another explosion occurred in the electrolysis cell view more

Incident Synopsis

A hydrogen explosion occurred in an emergency battery container used to transfer fuel elements. The container had five emergency power batteries. Damage was incurred by the explosion.

Cause

The H2 concentration in the container increased because the battery charger had been left on charge. In addition, the container was placed in an un-ventilated airlock. Ignition of the H2-air mixture was believed to be caused by the relays and micro switches activated when the airlock door was opened.