To Convert:                 Into:                        Multiply By:
 ─────────────────────────── ──────────────────────────── ──────────────────
 btu (60°F)                  btu                          1.00031
 btu (60°F)                  btu (IST)                    0.999657
 btu (60°F)                  btu (mean)                   0.998873
 btu (60°F)                  btu (39°F)                   0.995291