Safety considerations:
1. The installer should wear proper protective clothing, gloves, eye protection as the aluminum foil have a strong reflectivity rate.
2. Be especially careful with electrical wiring, particularly around junction boxes and old wiring. Never staple through or near the electrical wiring. 
3.Watch carefully when you walk on the attic or roof etc. 
4. Work with a partner. Not only for making the job go faster, it also means that you'll have assistance if a problem occurs. 
5.Work at a reasonable temperature.