Sometimes we say “fallout shelter” and “bunker” so that people will find us, but we want to be clear: We Sell Blast Shelters

Many people use the phrases “bomb shelters,” “blast shelters,” “fallout shelters” and “bunkers” interchangeably. The engineering definitions are very different.

What is a Blast Shelter?

A blast shelter is the correct choice for protection from full-scale protracted nuclear-biological-chemical war. It protects individuals from both the nuclear bomb blast and its gamma and neutron radiation. All NORAD S-Series shelters are “blast shelters.”  The blast and radiation protection is common to all NORAD S-Series Underground Shelters.

Blast Shelters Protect From Sustained Fires, 10 to 40 psi Over Pressure and Radiation for a Minimum of 30 Days.
Blast Shelters Protect From Sustained Fires, 10 to 40 psi Over Pressure and Radiation for a Minimum of 30 Days.

What About EMP?

Although not a requirement to classify as a “blast shelter,” all with the option are EMP shielded to MIL-188-125, the Department of Defense standard for EMP protection. EMP Protection is standard in NORAD Military blast shelters and optional in NORAD Civilian shelters.

Blast Shelter Radiation Protection

To be a “blast shelter,” the structure must have a TRS or Total Rems in Shelter rating. The TRS indicates how many rems the shelter occupants will receive at specific distances from ground zero from overhead, entranceways and air ducts. NORAD S-Series Underground Shelters have a TRS of 4-10. Shelterists will receive a maximum of 2 rems radiation at Point Z during a bomb blast creating 10 psi over pressure (see Point Z image below). The TRS measures all forms of radiation from all shelter exposure points.Neutron radiation particles have a total life of not more than 60 seconds. They have the greatest ability to penetrate heavy barriers. Neutron radiation traveling through 45 inches of earth will be reduce to 1/1000th. Fallout shelters do not protect from neutron radiation. Blast shelters do protect from neutron radiation.Gamma radiation particles travel at the speed of light (186,000 miles per second). Gamma radiation is reduced to 1/1,000 in traveling through 55 inches of earth.Both blast shelters and fallout shelters protect from gamma radiation by being strong enough to occupy when hundreds of thousands of pounds of earth are overhead. NORAD S-Series Blast Shelters use high strength structural steel Beams providing much more strength than is required for the depth buried. All NORAD S-Series shelters come with a Cathodic Corrosion Protection System. Steel fallout shelters not offering corrosion protection need to be de-rated two to 5% each year. Because the Corrosion Protection system maintains the shelter’s structural integrity from blast and earth pressure, the shelterists are safe for 30-50 years.  All NORAD S-Series shelters include a  formal cathodic protection system allowing a 30-50 year structural integrity  warranty..

What is a Fallout Shelter?

A fallout shelter provides gamma radiation protection but not neutron radiation protection. A “fallout shelter” does NOT provide blast protection. A “fallout shelter” provides a 30 day life support system.

What is a Bunker?

A bunker is not a very useful protection device. It’s a very short term structure that is not designed to protect individuals from nuclear, biological and chemical threats since it typically has no life support equipment. Emergency Bunkers protected individuals from conventional bomb blasts during the world wars.

NORAD Sells Blast Shelters

Our website sometimes refers to our “fallout shelters” and “bunkers” because we want people to find us using lay-person vocabulary. We want our customers to understand that we sell BLAST SHELTERS that protect individuals from nuclear weapon blast and subsequent gamma and neutron radiation.Learn more about the Reality of Underground Shelter Types and Ratings.

Shelter Protection Summary

Blast shelters protect from neutron radiation, gamma radiation, up to 40 psi blast over pressure, for a minimum of 30 days. Fallout shelters protect from gamma radiation for a minimum of 30 days, but do not protect from neutron radiation or blast over pressure. Bunkers do not protect individuals from nuclear explosions.NORAD Provides Safety Performance Data Documenting How Its Blast Shelters Protect Individuals from Radiation