HYDRAZOIC ACID

Chemical Identification
Chemical Identification
CAS # 7782-79-8
Formula

HN₃

Synonyms

azoimide; diazoimide; hydrogen azide; hydronitric acid; triazoic acid

Physical Properties
Physical Properties
Physical description Colorless liquid with an intolerable pungent odor.
Boiling point 96.26°F Molecular weight 43.03
Freezing point/melting point -112°F Vapor pressure 484 mmHg
Flash point Vapor density
Specific gravity 1.09 Ionization potential
Lower explosive limit (LEL) Upper explosive limit (UEL)
NFPA health rating NFPA fire rating
NFPA reactivity rating NFPA special instruction
Vapor hazard ratio (VHR)
Historical exceedance percentage
Target organs
Monitoring Methods Used by OSHA
Monitoring Methods Used by OSHA
Analyte code (IMIS no.) 2243
Sampling group
Sampler/Sampling media 37 mm PVC filter and Silica gel tube(150/75 mg) impregnated with NaOH, A Preweighted PVC Gravimetric Filter is used to collect particulate azide [SKC 226-55 & SLTC108]
Sampling time*

5 minute minimum

 

 

Sampling volume (TWA)*
 

 

Sampling flow rate (TWA)*
 

 

 

 

Sampling volume (STEL/Peak/C)*
 

5 L (minimum)

 

 

Sampling flow rate (STEL/Peak/C)*
 

1 L/min

 

 

Analytical method instruments
Method reference OSHA ID-211 (fully validated)
Notes
 
  • The silica gel is coated with a reactive substrate. After collection submit samples to the laboratory using normal shipping procedures as soon as possible. At the lab, refrigerate samples until analysis.
  • The TLV-Ceiling for sodium azide is 0.29 mg/m³ measured as sodium azide, and is 0.11 ppm measured as hydrazoic acid vapor. The basis for this dual TLV is that sodium azide has high solubility in water and will form hydrazoic acid in water, that hydrazoic acid vapor is present where sodium azide is handled, and that sodium azide is used to produce hydrazoic acid. The same sampling method (OSHA ID-211) is used for both substances and it is possible that both chemicals will be present in the same sample. The analytical method cannot differentiate between the two chemicals, and the section of the sampler where the substance is found serves as the basis for identification of the chemical substance. Analytical results are usually expressed as sodium azide. It is essential that analytical results be expressed as only one of the two chemical substances so that sample results can be compared to the appropriate TLV-Ceiling.

 

 

Exposure limit for NAIMA is 1.0 f/cc

Special requirements
 

 

 

 

* All sampling instructions above are recommended guidelines for OSHA Compliance Safety and Health Officers (CSHOs), please see the corresponding OSHA method reference for complete details.

Wipe Method
Wipe Method
Sampler/Sampling media
 

 

Bulk Method
Bulk Method
 

 

On-Site Screening Techniques
On-Site Screening Techniques
Device
Model/Type
Sampling information
(see manufacturer instructions)
Exposure Limits
Exposure Limits
OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
NIOSH REL
Up to 10-hour TWA
(ST) STEL
(C) Ceiling
ACGIH TLV©
8-hour TWA
(ST) STEL
(C) Ceiling
CAL/OSHA PEL
8-hour TWA
(ST) STEL
(C) Ceiling
Peak
PEL-TWA
 

 

REL-TWA
 

 

TLV-TWA
 

 

PEL-TWA
 

 

PEL-STEL
 

 

REL-STEL
 

 

TLV-STEL
 

 

PEL-STEL
 

 

PEL-C
 

 

REL-C
 

0.1 ppm

TLV-C
 

0.11 ppm [1992]

PEL-C
 

 

Skin notation
 

NA

Skin notation
 

Y

Skin notation
 

N

Skin notation
 

NA

Notes:
 

Not established

Notes:
 

as (HN₃)

Notes:
 

as Hydrazoic acid vapor

Notes:
 

Not established

Health factors:  See NIH-NLM PubChem. IDLH
Carcinogenic classifications: Notes:
 

 

AIHA emergency response planning guidelines - ERPG-1/ERPG-2/ERPG-3:
 

 

Additional Resources and Literature References
Additional Resources and Literature References

NOAA: CAMEO Chemicals - Sodium azide

NIOSH: Pocket Guide to Chemical Hazards - Sodium azide

Literature References

 

 

Last Updated Date : 12/31/2020