Pressure Relief Valves

Designed to provide customers with the widest selection of sizes, orifices and construction materials, Series 2700 meets the exacting demands of the process industry. Superior Design A single design handles air, steam, vapor and liquid services. Maximum interchangeability of parts affords easy maintenance and lower costs. Fixed blowdown design simplifies testing and repair. Maximum blowdown of 5% to 15% regardless of service.1 A built-in lift stop ensures stable performance. Balanced design in “C” and “D” orifices nullifies the effects of back pressure on set point. ASME Code Certification Manufactured...

Numbering System Selecting and specifying Farris pressure relief valves is simple using the numbering system that follows. Each digit of the type number has a distinct significance. The digits describe the basic valve series, orifice, seat design, inlet temperature range, body, bonnet and spring material, inlet type and pressure rating. Special Variations Inlet Connections Special Materials Series Number Orifice Area Seat Construction H High pressure variations of standard types B Balanced design3 D Heat transfer fluid standard pressure E Heat transfer fluid high pressure M1 Monel Body & Disc...

2700 Series – Conventional Bill of Materials – Conventional Item Complies with ASME Boiler & Pressure Vessel Code, Section VIII Part Name Bonnet Disc Guide Disc Holder Stem Spring Adj. Screw Jam Nut Cap, Plain Screwed Cap Gasket Body Gasket Guide Gasket Spring (-50°F to +750°F) Spring Buttons Wire Seal Nameplate (Not Shown) Welding Nipple (Inlet) Welding Nipple (Outlet) Lap Joint Stub End (Inlet) Lap Joint Stub End (Outlet) Lap Joint Flange (Inlet) Lap Joint Flange (Outlet) Standard Material SA-351, Gr. CF8M St. St. or SA-479 Type 316 St. St. SA-216, Gr. WCB, Carb. St. 316 St. St. 316 St. St....

2700 Series – Balanced Design Complies with ASME Boiler & Pressure Vessel Code, Section VIII Do you have variable back pressure? Can’t use a balanced bellows design? Farris has the solution with the Series 2700 Balanced Design pressure relief valve. The balanced effect is achieved by isolating the upper valve chamber and eliminating any back pressure build-up in the bonnet effecting valve set pressure. These valves are available in 1/2", 3/4" and 1" inlet sizes with a 1" outlet and two orifice areas. Pressure ranges from 15 to 1480 psig, standard soft seat design. Flanged and welded inlet and...

O-Ring Selection The 2700 Series is available with an optional O-ring seat which minimizes fugitive emissions and costly product loss. This optional seat construction provides zero bubbles per minute leakage at 90% of set pressure per API Standard 527. The tables below list the set pressure and temperature range for both the elastomer and Teflon seat options. O-Ring Seat Valve Pressure & Temperature Limits Pressure Range, psig1 Elastomer Seat Teflon Seat C High Pressure D High Pressure E F G Pressure Range, barg1 Elastomer Seat Teflon Seat Material Availability Material Viton® Buna N EPR Silicone...

Selection Table – Conventional Design Flanged Connections, U.S. Customary Units Orifice Area Sq. In. Valve Size Inlet x Outlet ANSI Flange Class Inlet RF Maximum Set Pressure, psig Type Number Max. Back Pressure psig at 100°F Materials Body / Bonnet Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel Stainless Steel General Notes: 1. vailable with optional elastomer or Teflon seat design as illustrated. Change the fourth digit of the type number from “A” to “C” for soft seat, “A” to “T” for Teflon. Example: A 27DC23-M20...

Selection Tables – Balanced Design (see notes on page 5) Threaded Connections – MNPT X FNPT, U.S. Customary Units Orifice Area Sq. In. Valve Size Inlet x Outlet Type Number Maximum Set Pressure, psig -20°F to 450°F Max. Back Pressure psig at 100°F Stainless Steel Stainless Steel Materials Body / Bonnet Spring Flanged Connections, U.S. Customary Units Orifice Area Sq. In. Valve Size Inlet x Outlet ANSI Flange Class Inlet RF Type Number Maximum Set Pressure, psig -20°F to 400°F 100°F Max. Back Pressure psig at 100°F Materials Body / Spring Bonnet Stainless Steel Stainless Steel Stainless Steel...

Special Materials Corrosive & Low Temperature Service Part Name Disc Guide Disc Holder Stem Spring Adj. Screw Jam Nut Cap, Plain Screwed Cap Gasket Body Gasket Guide Gasket Spring Buttons O-Ring Retainer5 Retainer Lock Screw5 O-Ring Seat Seal5 Guide Seal5 Disc Holder Seal5 Wire Seal Nameplate (Not Shown) Welding Nipple (Inlet) Welding Nipple (Outlet) Lap Joint Stub End (Inlet) Lap Joint Stub End (Outlet) Lap Joint Flange (Inlet)4 Lap Joint Flange (Outlet)4 Monel Monel Monel 316 St. St. Monel Monel Inconel X-750 Monel Monel Monel Monel Monel Monel Monel Monel Monel Monel Monel Monel Monel Monel...

Capacity Tables – 2700 Series U.S. Customary Units: ASME Pressure Vessel Code, Section VIII (UV) Stamp AIR – 10% Overpressure Capacities in Standard Cubic Feet Per Minute at 60°F Set Pressure (psig) STEAM – 10% Overpressure Capacities in Pounds Per Hour at Saturation Temperature Set Pressure (psig) General Notes: 1. apacities at 30 psig and below are based on 3 psi overpressure. C 2. or sizing purposes, the coefficients of discharge K are 0.878 for air, gas & steam; F 0.676 for water.

Capacity Tables – 2700 Series U.S. Customary Units: ASME Pressure Vessel Code, Section VIII (UV) Stamp WATER – 10% Overpressure Capacities3 in U.S. Gallons Per Minute at 70°F Set Pressure (psig) 9 General Notes: 1. apacities at 30 psig and below are based on 3 psi overpressure. C 2. or sizing purposes, the coefficients of discharge K are 0.878 for air, gas & steam; F 0.676 for water. 3. o determine capacity at 25% overpressure, multiply the capacity at 10% by 1.066. T