Mechanical Seal Style FCSA

API Dry-Running Secondary Containment Seal

Designed for Safe Fluid Containment & Environmental Emission Control

In certain processes, dangerous and volatile fluids require additional precautions to protect personnel, ensure safe operation, and prevent downtime. The Flexaseal Multi-Spring Fluid Containment (FCS) Seal has been specifically designed as an economical option for applications where the highest level of safety and environmental control is necessary. The FCSA Seal allows monitoring of any primary seal leakage and functions as a secondary containment seal in the event of any primary failure.

The FCSA Seal is a contacting, dry-running multi-spring pusher seal which can be added to most of Flexaseal’s single cartridge options, including:

  • Style 58 heavy duty API stationary multi-spring cartridge seal
  • Style 53A API rotating welded metal bellows cartridge seal
  • Style SMS stationary multi-spring cartridge seal
  • Style RB rotating welded metal bellows cartridge seal
Mechanical Seal FCSA Seal


    • Lightly loaded seal face minimizes wear and face temperature
    • Extended seal face has long wear life
    • Balanced design minimizes heat generation and power consumption and guarantees stable operation under worst-case containment scenarios
    • Isolation bushing keeps normal inboard seal leakage away from the FCSA seal
    • Dynamic drive ring prevents pin-wear hang up
    • Most commonly used with API 682 Plans 72, 75, and/or 76


Materials of Construction

Faces: Special Dry-Running Carbon, Reaction-bonded Silicon Carbide
Elastomers: Fluoroelastomer (Viton®), Ethylene Propylene, TFE Propylene (Aflas®), Buna, Neoprene, Perfluorelastomers (Kalrez, Chemraz)
Metallurgy: 316 stainless steel, Hastelloy® C-276, Super Duplex alloy 255 or Titanium
Springs: Hastelloy® C-276

Operating Parameters

Speed: 10000FPM (50 m/sec)
Temperature: up to 550°F (288°C) using high temperature elastomers

Gas-lubricated: up to 10 psig (0.7barg).

Liquid-lubricated: up to 300 psig (20.7 barg), dynamic.

Liquid-lubricated: up to 600 psig (41.4 barg), static.

Note: Max Temperature / pressure / speed indicate operating extremes independently and do not imply the seal will function at these extremes at the same time.