Safety

To many, hydrogen is associated with explosiveness. In fact, it does burn like any other fuel.

However, combustion can’t occur in a tank that contains only hydrogen. Oxygen (or air) and an ignition source are required for combustion and explosions to occur. Hydrogen tanks are purged of Oxygen and other gases  with inert gas as Nitrogen (N₂) or Helium, so it cannot explode.

Like any fuel, hydrogen can combust. However, it dissolves in air very quickly and it is hard to reach the flammability concentration.

In order for a hydrogen fire to occur, an adequate concentration of hydrogen, the presence of an ignition source and the right amount of oxidizer (like oxygen) must be present at the same time.

If hydrogen catches fire, it will burn very quickly without producing toxic smoke, and heating the surrounding structures much less than common fuels does.

Also, as hydrogen fires have low radian heat, the safety distance is three times less with respect to common carbon fuel fires.

An ignition cannot occur in a tank or any contained location that contains only hydrogen. An oxidizer, such as oxygen must be present in a concentration of at least 10% pure oxygen or 41% air.

Hydrogen is the lightest element in the world and volatilizes very rapidly in air, giving it a major advantage over Gasoline, which dissipates more slowly and is heavier than air. Gasoline therefore stays on the ground longer, where the threat of ignition is highest.

Gasoline and hydrogen also burn differently. If liquid Gasoline leaks, spreads onto a surface and burns, it produces a very broad flame that emits a large amount of heat. In contrast, hydrogen burns with a narrow almost perpendicular flame that does not emit much heat. Unlike a bright Gasoline flame, a pure hydrogen flame is difficult to see in daylight.

Hydrogen’s overall ignition properties are generally more favorable than today’s common energy carriers.

Gasoline’s flammability limit (0.6 volume percent) and explosion limit (1.1 volume percent) are very close together, which means that when Gasoline ignites, there is almost always the danger of explosion.

Hydrogen’s flammability limit of 4 volume percent and its explosion limit of 18 percent are much further apart. At 0.24 mill joules, however, Gasoline’s minimum ignition energy threshold is significantly higher than hydrogen’s– although the energy in a spark is still sufficient to ignite Gasoline. And Gasoline’s relatively low auto-ignition temperature (220 to 280 degrees Celsius) also means that it can ignite on contact with hot metal parts such as a catalytic converter or exhaust manifold.

This is not the case with hydrogen, which has an auto-ignition temperature of 585 degrees Celsius.

Simply stated, to become a fire hazard, hydrogen must first be confined – but as the lightest element in the universe, confining hydrogen is very difficult.

Industry takes these properties into account when designing structures where hydrogen will be used. The designs help hydrogen escape up and away from the user in case of an unexpected release.

Hazardous areas are protected by 4 protective shields:

• Double wall pipes to prevent leaks
• All pipes are equipped with leak detectors
• Electric Spark free Components
• 30x per hour Ventilations

The measures described above, make dangerous areas more safe and secure more than any other fuel.

For over 40 years, industries have used hydrogen in vast quantities as an industrial chemical and fuel for space exploration. During that time, industries have developed an infrastructure to produce, store, transport and utilize hydrogen safely.

Industries have safely used hydrogen in the following applications:

• Petroleum refining
• Glass purification
• Semiconductor manufacturing
• Aerospace applications
• Fertilizer production
• Welding, annealing and heat-treating metals
• Pharmaceuticals
• As a coolant in power plant generators

For hydrogenation of unsaturated fatty acids in vegetable oil

A hydrogen-air mixture is always lighter than air alone, therefore it will rise upwards. As a result there is no danger that the gas mixture will build deposits in cellars, trenches, underground garages, in the canalization system, etc.

Within buildings, gas detectors are installed which, in the unlikely event of a gas release with a concentration of 1.6% of hydrogen or higher, will immediately shut down the system and bring it to a safe state so that the hydrogen concentration cannot increase anymore.

An outdoor leak would simply rise quickly and diffuse.

On the contrary, liquid fuels or heavy gases tend to accumulate on the ground, a fact that makes them even more dangerous.

Leaks of small quantities of hydrogen are possible, because hydrogen is such a small molecule.

However:

• It dissolves in air very quickly so it’s hard to reach dangerous concentration;
• Gas detector, Extra ventilation (30x/hour) and shut-off valve are typical safety measures undertaken to avoid any risk.

Flames are always dangerous if not kept under control. They can damage and burn surfaces, hurt people who are not at a safety distance and they may produce smoke which may suffocate.

However:

• A Hydrogen propulsion system with fuel cells does not use combustion, it produces electricity to power the ship by chemical reaction, such as a battery.
• Hydrogen combustion does not create toxic smoke, as carbon fuels do.
• The safety distance from a hydrogen fire is three times less than a fossil fuel fire.
• Hydrogen burns with a narrow almost perpendicular flame that does not emit much heat, compared to other carbon fuels. But, hydrogen flames are nearly invisible.

Because a hydrogen fire doesn’t radiate as much heat as most fires do, it is less likely to cause secondary fires.

With the exception of oxygen, any gas can cause asphyxiation. In most scenarios, hydrogen’s buoyancy and diffusivity make hydrogen unlikely to be confined where asphyxiation might occur.

Hydrogen is non-toxic and non-poisonous. It will not contaminate groundwater (it’s a gas under normal atmospheric conditions), nor will a release of hydrogen contribute to atmospheric pollution. Hydrogen does not create “fumes.”

Any cryogenic liquid (hydrogen becomes a liquid below –252.8°C) can cause severe freeze burns if the liquid comes into contact with the skin.

However, to keep hydrogen ultra-cold today, liquid hydrogen containers are double-walled, vacuum-jacketed, super-insulated containers that are designed to vent hydrogen safely in gaseous form if a breach of either the outer or inner wall is detected. This robust construction and redundant safety features dramatically reduce the likelihood for human contact.

The branches of physics and engineering that involve the study of very low temperatures, how to produce them, and how materials behave at those temperatures.

Cryogenic liquids are liquefied gases that are kept in their liquid state at very low temperatures. Cryogenic liquids have boiling points below -150°C (- 238°F) and small amounts of liquid can expand into very large volumes of gas.

The vapors and gases released from cryogenic liquids also remain very cold. They often condense the moisture in air, creating a highly visible fog.

The fire that destroyed the Hindenburg in 1937 gave hydrogen a misleading reputation. Hydrogen was used to keep the airship buoyant and was initially blamed for the disaster.

An investigation by Addison Bain in the 1990s provided evidence that the airship’s fabric envelope was coated with reactive chemicals, similar to solid rocket fuel, and was easily ignitable by an electrical discharge.

The Zeppelin Company, builder of the Hindenburg, has since confirmed that the flammable, doped outer cover is to be blamed for the fire. For more information, view a short video at: www.HydrogenAssociation.org.

The hydrogen in Nature is commonly found in its isotope form, the Protium. H-Bomb technology uses a rare hydrogen isotope called Tritium.

Both Tritium plus the super-intense heat from the detonation of a nuclear fission bomb are needed to induce the nuclear fusion reaction that makes a hydrogen bomb.

Tritium is radioactive and does not occur naturally, but can be made with lithium or a conventional nuclear reactor.

This technology bears no resemblance to the simple chemical reactions associated with the Protium hydrogen isotope in hydrogen production, storage, distribution and use in the hydrogen market.