Cov khoom tawg-pov thawj yog tsim los ntawm lub hauv paus ntsiab lus uas cov khoom siv nws tus kheej yuav tsis dhau los ua qhov chaw ntawm qhov hluav taws kub hauv qhov chaw tawg, thiab nws yuav tsis tsim cov pa taws lossis overheat rau saum npoo.
Chav Kawm I: cov khoom siv hluav taws xob hauv av hauv cov mines;
Chav Kawm II: cov khoom siv hluav taws xob rau tag nrho lwm cov pa roj cua tawg tsuas yog cov mines thee thiab cov mines hauv av.
Chav II tuaj yeem muab faib ua chav kawm IIA, IIB thiab IIC. Cov khoom siv cim nrog IIB tuaj yeem siv rau kev ua haujlwm ntawm cov khoom siv IIA; IIC tuaj yeem siv rau kev ua haujlwm ntawm IIA thiab IIB.
Chav Kawm III: Cov khoom siv hluav taws xob hauv cov huab cua tawg tawg uas tsis yog cov mines thee.
Chav Kawm IIIA: flammable ya flocs; Chav Kawm IIIB: tsis yog-conductive plua plav; Class IIIC: conductive plua plav.
Daim ntawv pov thawj tawg
1. Intrinsically muaj kev nyab xeeb "i" (cov khoom siv hluav taws xob muaj kev nyab xeeb thiab cov khoom siv sib txuas) Intrinsically safe circuits:
2. Flameproof hom "d" Cov khoom siv hluav taws xob nrog cov ntaub ntawv flameproof.
3. Muaj kev nyab xeeb ntxiv e
4. Roj puv o
5. Xuab zeb sau hom q
6. Encapsulation hom m
7. Sib tov
