Yes diploma in fire engineering can be pursued after 12th commerce.

Diploma in Fire and Safety Management is a full-time diploma course, the period of this course can be  1 or 2 years (generally one year) depending upon the college and the curriculum they follow. It is an open course that helps students to get better job opportunities and promotion in their field as fire and safety officer, health and safety manager, in charge manager.

The Diploma in Fire and Safety Management course focuses  on training  students in the prevention of fire and safety methods.

Also follow the below link from careers 360 to get more information about diploma in fire engineering.

https://engineering.careers360.com/colleges/list-of-diploma-in-safety-and-fire-engineering-colleges-in-india