Document: NRC Regulatory Guide
Document ID: ceaeb6d7-d85a-46d3-a1b6-70059a498965
Document Type: regulatory_guide
Title: 12/2001 (Rev. 1)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0131/ML013100014.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.78
CFR Part: 
CFR Title: 

Content:
nhydrous ammonia Aniline Benzene Butadiene Butene Carbon dioxide Carbon monoxide Chlorine Ethyl chloride Ethyl ether Ethylene dichloride Ethylene oxide 2000 2500 85 300 100 500 2000 40000 1200 10 3800 1900 50 800 3600 6000 149 210 380 1600 4400 asphyxiant 7360 1320 30 9880 5700 200 720 Fluorine Formaldehyde Halon 1211 Halon 1301 Helium Hydrogen cyanide Hydrogen sulfide Methyl alcohol Nitrogen (compressed or liquified) Sodium oxide Sulfur dioxide Sulfuric acid Vinyl chloride Xylene 25 20 20000 50000 50 100 6000 100 1000 900 50 24 asphyxiant 55 150 7800 asphyxiant 2 520 15 2600 3915 This table lists commonly encountered chemicals but the list is not all-inclusive. A more complete list of chemicals is in Reference 5. a Adapted from NUREG/CR-6624, “Recommendations for Revision of Regulatory Guide 1.78” (Ref. 5). b Parts of vapor or gas per million parts of air by volume at 25C and 760 torr (standard temperature and pressure). c Approximate milligrams of particulate per cubic meter of air, at standard temperature and pressure, based on listed ppm values.  For release of hazardous chemicals from stationary sources or from frequently shipped mobile sources in quantities that do not meet the screening criteria, detailed analysis should be performed for control room habitability. Licensees are encouraged to make use of risk information, particularly when requesting related license amendments. The guidance for risk evaluation is provided in Regulatory Position 2. Licensees may continue to use the traditional engineering approach for control room habitability evaluation; the guidance for this approach is provided in Regulatory Position 3. 2. RISK EVALUATION For releases of hazardous chemicals from stationary sources or from frequently shipped mobile sources in quantities that do not meet the screening criteria in Regulatory Position 1.1 or 1.78-6 1.2, detailed analyses should