It belongs to the industry recommended non-compulsory standards are clearly marked "GB/T", T that is, recommended, non-compulsory.
The state did not stipulate that "villa ladder is not mandatory acceptance", but the mandatory acceptance of the elevator range does not include villa ladder,
and the implementation of a series of recommended norms. As for the recommended norms you do not do, that is your business,
Do the best, do not do is not illegal.
For the customer, you tell him that there is no mandatory acceptance in the national standard, so you can not accept, which is based on.
Again, people ask for acceptance, you let them acceptance.