Gas engineers must be on the register to do safe and legal gas installations and  service gas home equipment. http://nguyenkhuyen-nuithanh.edu.vn/index.php?language=vi&nv=news&nvvithemever=d&nv_redirect=aHR0cHM6Ly9qb2JzMjUxLmNvbS9hdXRob3Ivc291cHdpdGNoNDkv