Helium

  • Helium, compressed
Formula
He
Structure
Description
A colorless, odorless, tasteless gas. It is chemically inert. When shipped as a liquid it is very cold and will solidify all other gases.
Uses
Diluent for gases, liquid helium is used for production of low temperature, inert, nonflammable gas used for balloons & airships, in lasers, nucleonics & rocket research.

Registry Numbers and Inventories.
CAS
7440-59-7
EC (EINECS/ELINCS)
231-168-5
RTECS
MH6520000
RTECS class
Other
UN (DOT)
1046
Beilstein/Gmelin
16294 (G)
Swiss Giftliste 1
G-9569
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Korea ECL
Listed

Properties.
Formula
He
Formula mass
4.00
Melting point, °C
-272.2
Boiling point, °C
-268.94
Vapor pressure, mmHg
1560 (-268 C)
Vapor density (air=1)
0.138
Critical temperature
-267.9
Critical pressure
2.26
Density
0.176 g/L (25 C)
Solubility in water
8.8 g/L
Viscosity
3.5E-5 P (270 C)
Surface tension
9.6 g/s2 (268 C)
Refractive index
1.035 - 1.1811 (25 C)
Thermal expansion
0.00366/K (0 C)
Heat of vaporization
0.081 kJ/mol

Hazards and Protection.
Storage
Cylinders should be stored and used in dry, well ventilated areas, away from heat sources.
A
Handling
Handle in accordance with all current regulations and standards.
Protection
Wear appropriate protective gloves, clothing and goggles. Always wear thermal protective clothing when handling refrigerated/cryogenic liquids.
Respirators
Wear positive pressure self-contained breathing apparatus (SCBA).
Small spills/leaks
Attempt to stop leak if without undue personnel hazard.
Stability
Stable at room temperature and pressure.
Incompatibilities
None.
Decomposition
None.

Fire.
Fire fighting
Extinguish fire using agent suitable for type of surrounding fire. (Material itself does not burn.) Cool all affected containers with flooding quantities of water. Apply water from as far a distance as possible.
Fire potential
Nonflammable gas.
Hazards
Containers may explode when heated. Ruptured cylinders may rocket.
Combustion products
None.
Health
1
 
Flammability
0
 
 
Reactivity
0
 

Health.
Poison_Class
-
Exposure effects
Rapid breathing and rapid heart rate are common. In severe cases abnormally low blood pressure, apnea, and cardiac arrest develop. Various disturbances including headache, dizziness, mood disturbances, numbness of the extremities, sleepiness, mental confusion, poor judgement and coordination, and memory loss may occur. Prolonged or severe hypoxia results in unconsciousness. Prolonged asphyxia may produce CNS injury.
   Ingestion
Unlikely route of exposure.
   Inhalation
Hyperventilation may develop. Vapors may cause dizziness or asphyxiation without warning.
   Skin
Contact with gas is not expected to cause problems unless at low temperature. At low temperature, frostbite may be observed.
   Eyes
Decreases in night vision, visual acuity, and visual fields (tunnel vision) may occur. Frothy mucous may be seen.

First aid
 
   Ingestion
Seek medical assistance.
   Inhalation
Administer 100% humidified supplemental oxygen with assisted ventilation as required. If hypoxia has been severe or prolonged, carefully evaluate for neurologic sequelae and provide supportive treatment as indicated.
   Skin
Rewarming and a variety of topical treatments are indicated for frostbite injury. See main section for more information.
   Eyes
Irrigate exposed eyes with copious amounts of tepid water for at least 15 minutes. If irritation, pain, swelling, lacrimation, or photophobia persist, the patient should be seen in a health care facility.

Transport.
UN number
1046
Response guide
Hazard class
2.2
Std. Transport #
4904539