Convert Pound-force seconds per square foot to Poises
Convert Pound-force seconds per square foot (lbf·s/ft²) to Poises (P) instantly and accurately.
Conversion Formula
P = lbf·s/ft² × 478.8025898
About Pound-force seconds per square foot
The pound-force second per square foot (lbf·s/ft²) equals (9.80665 × 0.45359237) / 0.3048² ≈ 47.880 Pa·s, numerically identical to slug/(ft·s). It appears in US civil and structural engineering fluid mechanics, pump hydraulics texts, and older API pipeline standards. A key identity: 1 lbf·s/ft² = 1 slug/(ft·s) ≈ 47.880 Pa·s = 478.8 P.
About Poises
The poise (P) equals 0.1 Pa·s (exact), defined in the CGS system as 1 g/(cm·s). Named after Jean Louis Marie Poiseuille, it was the dominant viscosity unit before SI adoption. Fluid-mechanics textbooks and older ASTM and API data tables still list viscosities in P. Motor oil at 100 °C is ≈0.02-0.05 P; water at 20 °C is ≈0.01 P (= 1 cP). 1 P = 0.1 Pa·s = 100 cP.
Quick Reference Table
| Pound-force seconds per square foot (lbf·s/ft²) | Poises (P) |
|---|---|
| 1 lbf·s/ft² | 478.803 P |
| 2 lbf·s/ft² | 957.605 P |
| 5 lbf·s/ft² | 2394.01 P |
| 10 lbf·s/ft² | 4788.03 P |
| 25 lbf·s/ft² | 11970.1 P |
| 50 lbf·s/ft² | 23940.1 P |
| 100 lbf·s/ft² | 47880.3 P |