Ngwa ngwaahịa:
bioengineering, nri, mmiri ara ehi, ọgwụ, dị ọcha mmiri, electronic engineering, chemical fiber Industry, chemical ụlọ ọrụ, akwụkwọ, biya, elu-ọcha gas, ntecha na ndị ọzọ ọrụ.
Ọkọlọtọ nnabata:
| ASTM A270 EN10357 |
| DIN 11850 |
| JIS G3447 |
| ISO 2037 |
| EN 1035T |
| AS 15281 |
| QB/T 2072.3 |
