1. Welding
Welding should not be performed except in designated areas. Any part to be welded should be removed from the aircraft, if possible. Repair would then be accomplished in the welding shop under controlled environment.
A welding shop should be equipped with proper tables, ventilation, tool storage, and fire prevention and extinguishing equipment.
Welding on an aircraft should be performed outside if possible.

2. welding in the hangar - precautions
No open fuel tanks or work on fuel systems should be in progress.
No painting in progress.
Only qualified welders should be permitted to do the work.
The area should be roped off and placarded.

3. Conti..
Fire extinguishing equipment of a minimum rating of 20B should be in the immediate area with 80B rated equipment as a backup.
There should be trained fire watches in attendance at the above equipment.
Aircraft should be in towable condition, with a tractor attached, aircraft brakes off, and a qualified operator on the tractor with mechanics available to assist in the towing operation.
Hangar doors should be opened.

4. Compressed Air System
Compressed air is like electricity an excellent tool as long as it is under control.
Air hoses should be inspected frequently for breaks. Unsafe hose should be replaced immediately.
All connections should be kept in a "no leak condition".
In line oilers, if installed, should be maintained in operating condition.
The system should have, water sumps installed and they should be drained at regular intervals.

5. Conti..
5. Air used for paint spraying should be filtered to remove oil and water.
6. Never use compressed air to clean hands or clothing. Pressure can force debris into the flesh leading to infection.
7. Never use compressed air for "horse play".
8. Air hoses should be straightened, coiled, and properly stored when not in use.