Epoxy Grout Quantities · Skid Mounting · Industry Guidelines
Additional grout for equipment sole plates
Grout types, installation practices, expansion joints, and quality control
Industry practice specifies 2–4 inches of grout under main runner beams. Below 2 inches risks bond failure and incomplete flow; above 4 inches risks exotherm cracking in epoxy and shrinkage in cementitious. Three inches is the typical design value.
Epoxy grout (≥12,500 psi compressive, ~130 lb/ft³) resists vibratory fatigue and chemical attack from hydrocarbons, while cementitious grout can crack under recip pulsation loads. API 686 requires epoxy for rotating equipment whose dynamic loads exceed 25% of static loads — most compressor packages.
Industry practice: 10% for typical crews on accessible pours, 5% for highly experienced crews with good forms, 15–20% for first-time crews or difficult-access pours. The allowance covers formwork leakage, mixing loss, shoulder/chamfer overpour, and surface irregularities.
Typical cap extension is 2–4 inches beyond the skid edge. The shoulder protects the bond line from chipping and provides a chamfer for thermal expansion. All embedded items require 3/8" corner radii per industry practice to prevent stress risers.
Industry practice requires ≥12,500 psi compressive for epoxy grout. Cementitious precision grouts (e.g., MasterFlow 928) typically achieve 5,000–10,000 psi — adequate for static equipment but marginal for high-cycle dynamic loads. Tensile bond to steel should exceed 1,500 psi for epoxy.