Trim 8 3/4" S 800 NPT gate valve

[Maxvolonte]

Hello again colleagues. It is acceptable to sweep the thread of a NPT valve to be able to use it as a SW. I have rejected it, some suggestion about it, regardless the line service that I do not remember, but I am sure they are for drainage,
Attached photos,
Best regards

 

[mk3223]

It could be acceptable if the dimension is complied with the Code, such as B16.34.

 

[Maxvolonte]

Thanks mk3223, but warranty from manufacturer is already avoided? They should not be held responsible if it failures?

 

[mk3223]

To be clear, who cancelled the manufacturer warranty? Is the change was done without the manufacturer's consent?
If it's the case, the only option is to make sure the right material based on the right Code.