Static Electricity 2000 Edition

9.5 Explosives.
Most explosives and materials used as solid
propellants contain enough oxidizer to sustain an explosive
reaction without any outside contribution. These materials
typically are sensitive to static electric discharge and can be
extremely hazardous to handle if suitable precautions are not
taken. In addition to the recommendations contained in this
recommended practice, the following documents should be
consulted for more specific information:
(1) NFPA 495, Explosive Materials Code
(2) NFPA 498, Standard for Safe Havens and Interchange Lots for
Vehicles Transporting Explosives
(3) NFPA 1124, Code for the Manufacture, Transportation, and
Storage of Fireworks and Pyrotechnic Articles
(4) NFPA 1125, Code for the Manufacture of Model Rocket and
High Power Rocket Motors
(5) U.S. Department of Defense Standard 6055.9, Ammuni-
tion and Explosive Safety Standards
(6) U.S. Department of Defense Standard 4145.26M, Contrac-
tors’ Safety Manual for Ammunition and Explosives
(7) IME Safety Library Publication No. 3, Suggested Code of
Regulations for the Manufacture, Transportation, Storage, Sale,
Possession, and Use of Explosive Materials
(8) IME Safety Library Publication No. 17, Safety in the Trans-
portation, Storage, Handling, and Use of Explosive Materials
9.6 Cathode Ray Tube Video Display Terminals.
9.6.1
A static electric charge is commonly present on the face
of cathode ray tube (CRT) video display terminals, particularly
on color monitors and color television screens. This charge is
the direct result of the CRT’s high-energy electron beam “writ-
ing” the image on the inside surface of the screen. The charge
accumulates on the nonconductive surface of the screen and
can reach energies capable of igniting a flammable atmo-
sphere, if discharge occurs. Such an atmosphere can be cre-
ated by wiping the screen of an operating or recently operated
CRT with a cloth or tissue that is wet with commercial cleaners
that typically contain a flammable liquid such as isopropyl
alcohol or by using spray-on aerosol cleaners that use a flam-
mable gas propellant. The static electric charge can be
removed from the screen of the CRT by accessories or by
proper procedures (see 9.6.3). Other video display terminals,
such as liquid crystal displays, gas plasma displays, and vacuum
fluorescent displays, do not present similar static electric
effects. This does not mean, however, that these displays are
intrinsically safe for use in hazardous locations.
9.6.2
In an industrial environment that is classified as hazard-
ous in accordance with Article 500 of NFPA 70, National Electri-
cal Code
®
, only engineering methods are acceptable for
controlling the hazard. Due to the high voltages present, the
CRT should be enclosed in a purged or pressurized enclosure,
as described in NFPA 496, Standard for Purged and Pressurized
Enclosures for Electrical Equipment. To protect against a static
electric discharge from the screen’s surface, the screen cannot
be exposed to the surrounding environment but should be
located behind a window in the enclosure.

---

APPENDIX A