Government Fallout Shelter Bulletin

Reading these criteria for fall out shelters published by our government should show you the necessity of providing your own safe haven.

We were told that a updated bulletin was in the process of being published in the near future.



The purpose of this standard is to establish minimum criteria for application to the design, construction, or designation of a space in a building or other facility as a fallout shelter.


The scope of this standard extends to buildings, spaces, or other facilities designated for use as public fallout shelters. The standard establishes technical, architectural, and environmental criteria for public fallout shelters.


The standard furnishes minimum criteria which provide for the protection of occupants from nuclear fallout radiation in spaces whose habitability and environmental characteristics are governed by the prevailing emergency situation and the essential lifesaving purpose of the fallout shelter. The criteria to be met typically are different from criteria ordinarily required for buildings and spaces having an everyday use.

Section 3.1. The standard indicates objectives to be met in the design and designation of fallout shelters in new and existing buildings. If all of the objectives cannot be met, then primary consideration shall be given to providing radiation shielding. In such instances, plans shall be developed to include the other fallout shelter features at a later time.

Section 3.2. This standard for public fallout shelters is a minimum standard. Nothing contained herein shall be construed to preclude exceeding this standard for any fallout shelter, except as may cause noncompliance with other requirements for the shelter space which may be prescribed in the local building codes.



A FALLOUT SHELTER is any room, structure, or space designated as such and providing its occupants with protection at a minimum protection factor (PF) of 40 from fallout radiation resulting from a nuclear explosion.

PUBLIC FALLOUT SHELTER is any fallout shelter which is intended for use by or is accessible to the general public. Fallout shelters which are a part of a private residence and are intended for private use are not included.

SINGLE-PURPOSE FALLOUT SHELTER is a fallout shelter having no use or occupancy except as a fallout shelter.

DUAL-USE FALLOUT SHELTER is a fallout shelter having a normal, routine use and occupancy as well as an emergency use as a fallout shelter.

PROTECTION FACTOR, sometimes abbreviated as PF, is a numerical value which expresses the relation between the amount of fallout radiation that would be received in a protected location and the amount that would be received if unprotected in the same location.

EFFECTIVE TEMPERATURE is an empirical index which combines in a single number the effects of temperature, humidity, and air movement on the sensation of warmth and cold felt by the human body.



General. Nothing in this standard shall be construed as preventing the dual use or multiple use of normal occupancy space as fallout shelter space, providing the minimum requirements for each are met.

Mixed Occupancy. The occupancy classification shall be determined by the normal use of a building or space. When a normal-use space is designed to have an emergency use as a fallout shelter in addition to the normal use, the most restrictive requirements for all such uses shall be met.

Occupancy Separation. No occupancy separation is required between that portion of the space designed as a public fallout shelter and the remainder of the building. A plan indicating the fallout shelter space and its boundaries shall be furnished as a means of identifying the fallout shelter.

Space. Space allowances for use as a fallout shelter shall be as follows.

(a) Floor Area. A minimum of 10 sq. ft. of net floor area shall be provided per shelter occupant. Partitions, columns, areas occupied by moveable furniture or other materials within the fallout shelter space, and any areas within the fallout shelter space used for storage of shelter supplies may be included in net area.

(b) Head Room. A minimum head room of 6.5 ft. shall be provided.

(c) Volume. A minimum of 65 cu. ft. of net volume shall be provided per shelter occupant. Net volume shall be determined using the net area calculated for the space.


The minimum level of protection for public fallout shelters is PF 40. Protection factors shall be calculated using methods approved by the Federal Emergency Management Agency based upon publication TR-20 (Volume 1), Shelter Design and Analysis--Fallout Radiation Shielding, June 1976 edition. (<< Wouldn't you think some new information would be available since this date?)

Ventilation and Temperature

Ventilation of the fallout shelter space shall comply with the standards of Appendix C, TR-20 (Volume 3), Shelter Environmental Support Systems, May 1978 edition, available from the Federal Emergency Management Agency.

Fresh Air. A minimum of 3 cu. ft. of fresh air per minute per fallout shelter occupant shall be provided to prevent oxygen depletion and carbon dioxide buildup in the fallout shelter.

Effective Temperature. The fallout shelter shall have a ventilation rate sufficient to maintain a daily average effective temperature of not more than 82F (28C) with at least a 90-percent reliability of not exceeding that value during the year. Effective temperatures shall be determined using procedures contained in the Handbook of Fundamentals, 1977 edition, prepared by the American Society of Heating, Refrigerating, and Air-Conditioning Engineers, Inc. (ASHRAE). Zones of equal ventilation rates in cu. ft. of air per minute which meet the requirements of this section are shown in Figure 1.

Ventilation Systems. Ventilation systems for public fallout shelters shall be designed to provide the ventilation rates required by Section 7.2. during periods when electric power may not be available from public service utilities. Emergency electrical generators or positive natural ventilation flow for fallout shelters may be used to meet this requirement.

Temperature. A temperature of not less than 50F (10C) shall be maintained in the fallout shelter during the occupancy period.

Air Intake. Ventilation systems shall be designed so that the outside air intake opening is positioned not less than 2-ft. above any surface on which radioactive fallout could be deposited. The air intake opening shall be hooded or positioned to prevent deposits of radioactive fallout on the intake face.

Filters. Special filters are not required for ventilation systems for public fallout shelters. No filters are required for fallout shelter ventilation equipment if the face velocity at the outside air intake is less than 150 ft. per minute.


No special lighting is required for fallout shelters which receive natural light. Spaces without windows, above or below ground, shall be provided with a minimum lighting level of 2 footcandles at the floor. Normal lighting fixtures may be used for this purpose if they are powered by an emergency generator, or battery-operated lights may be used.


Structural design of the fallout shelter shall comply with the local building codes. No special structural arrangements are required for public fallout shelters.

Minimum Design Loads.

(a) Minimum Design Loads for Dual-Use Fallout Shelters. The design live load required for normal use shall apply for dual-use fallout shelters.

(b) Minimum Design Loads for Single-Purpose Fallout Shelters. The minimum design live load for floors in single-purpose fallout shelters shall be 40 lb. per sq. ft. The minimum design live load for roofs of single-purpose fallout shelters shall comply with the requirements of the local building codes.

Access and Egress

Public fallout shelters shall have no fewer than two widely separated means of access and egress leading to other spaces of the building or directly to the outdoors.

Means of access and egress for dual-purpose fallout shelters shall meet the requirements prescribed by the local building codes for normal, routine use of the space.

Means of access and egress for single-purpose fallout shelters shall aggregate at least one unit of egress width for every 200 fallout shelter occupants. In no case shall a single opening be less than 24-in, wide.

Emergency-type hatchways may be used as a means of access and egress, provided that at least one means of access and egress for the fallout shelter is a standard opening conforming to the requirements of the local building codes. Hatchways, if used, shall be a minimum size of 24-in. x 36-in.

Fire Resistance

Fallout shelters shall meet fire-safety requirements as indicated below.

(a) Dual-purpose fallout shelters shall comply with requirements applicable for normal occupancy of the space.

(b) Single-purpose fallout shelters shall provide a flame-spread rating for interior surfaces not exceeding 200 on the flame spread scale and 450 or less on the smoke test scale when tested in accordance with ASTM E-84.


Hazardous utility lines, such as steam, gas, and oil lines, shall not be located in or near the fallout shelter unless provision is made to control such lines by valving or other approved means which permits shut-off of flow through the fallout shelter. Valving or other controls shall be readily accessible from the fallout shelter and shall conform with the local mechanical and gas codes.


Toilets, either flush-type operating from the normal water supply system, or chemical or other types, shall be provided on the basis of one toilet per 50 fallout shelter occupants. Toilets may be outside the fallout shelter in other portions of the building provided that they may be reached by occupants of the fallout shelter without exposure to direct fallout radiation as defined in TR-20 (Volume 1), Shelter Design and Analysis--Fallout Radiation Shielding, June 1976 edition, available from the Federal Emergency Management Agency. Austere provisions, such as empty water containers, for disposal of waste may be considered as fulfilling this requirement.

Drinking Water

A minimum of 3.5 gallons of potable water shall be available for each fallout shelter occupant. If it cannot reasonably be assumed that the public water supply system will be operational at all times when the fallout shelter may be occupied, then other means shall be provided for meeting this requirement. Storage tanks, trapped potable water in building lines, or auxiliary water wells at or near the premises may be used to fulfill this requirement.

Supplies and Storage

Consideration shall be given to fallout shelter supplies and their storage, but provision of such supplies is not required. Supplies and other storage considerations for public fallout shelters are discussed in publication CPG 1-19, Guidance for Development of An Emergency Fallout Shelter Stocking Plan, July 1978, available from the Federal Emergency Management Agency.