HG/T 21528-2014
常压手孔
Handholes for atmospheric use
2014-07-09
HG/T 21533-2014
常压快开手孔
Quick open handholes for atmospheric use
2014-07-09
HG/T 21515-2014
常压人孔
Manholes for atmospheric use
2014-07-09
HG/T 21525-2014
常压旋柄快开人孔
Quick open manholes for atmospheric use
2014-07-09