litefoot
Addicted to ArboristSite
I found this table to adjust for altitude when performing compression tests:
Altitude Factor
1000 .9711
2000 .9428
3000 .9151
4000 .8881
5000 .8617
6000 .8359
7000 .8106
8000 .7860
It looks like a logarithmic curve starting at roughly 3% loss in pressure every 1000'. So at my elevation (5500'), I'd be looking at about a 15% loss. That explains why my as-new 361 only reads 148 psi. It's actually 170.
Altitude Factor
1000 .9711
2000 .9428
3000 .9151
4000 .8881
5000 .8617
6000 .8359
7000 .8106
8000 .7860
It looks like a logarithmic curve starting at roughly 3% loss in pressure every 1000'. So at my elevation (5500'), I'd be looking at about a 15% loss. That explains why my as-new 361 only reads 148 psi. It's actually 170.