This page includes excerpts from ASME, ANSI, NEMA and other agencies that develop standards for the valve and control industry. At the bottom of this page you will find links to these agency sites.

National Electrical Manufacturers Association (NEMA) Classifications for Electrical Equipment and enclosures

*NEMA classifications. The NEMA classifies electrical equipment and enclosures for industrial applications as follows:

I. General purpose Protects against indirect splashing of dust and light but is not dusttight; primarily prevents contact with live parts; used indoors and under normal atmospheric conditions.
II. Driptight Similar to type I, with addition of drip shields or equivalent; used where condensation may be severe as in cooling rooms and laundries.
III. Weather resistant Protects against weather hazards such as rain and sleet; used outdoors on ship docks, for construction work, and in tunnels and subways.
IV. Watertight (weatherproof) Must exclude at least 65 gal/mm (247 L/m) of water from 1-in (25-mm) nozzle delivered from a distance of not less than 10 ft (3 m) for 5 mm. Used outdoors on ship docks, in dairies, and in breweries.
V. Dusttight Provided with gaskets or equivalent to exclude dust; used in steel mills and cement plants.
VI. Submersible Design depends on specified conditions of pressure and time; used for submersion in water, as in quarries, mines, and man holes.
VII. Hazardous location (explosive gas or vapor) Meets application requirements class I of National Electrical Code; conforms with specifications of Underwriters' Laboratories, Inc.; used for atmosphere containing gasoline, hexane, naphtha, benzine, butane, propane, acetone, benzol, lacquer-solvent vapors, and natural gas.
Type 8 enclosure (hazardous locations, oil-immersed) Type 8 enclosures are for indoor or outdoor use in locations classified as class I, Groups A, B, C, or fl as defined in the National Electrical Code.
Type 9 enclosure (hazardous locations, dust-ignition proof) Type 9 enclosures are for use in indoor locations classified as class II, groups E, F, or G, as defined in the National Electrical Code.
IX. Hazardous locations (combustible dust) Meets application requirements class II of National Electrical Code; conforms with specifications of Underwriters' Laboratories, Inc.; used for atmospheres containing metal dusts, carbon black, coal or coke dust, flour, starch or grain dusts.
ASME B16.34 - Valves - Flanged, Threaded, and Welding End
Scope: This standard applies to new valve construction and covers pressure-temperature ratings, dimensions, tolerances, materials, non-destructive examination requirements, testing, and marking for cast, forged and fabricated flanged, threaded and welding end and wafer or flangless valves of steel, nickel-based alloys, and other alloys.

ASME B16.11 - Forged Fittings, Socket-Welding, and Threaded
Scope: This standard covers ratings, dimensions, tolerances, markings and material requirements for forged fittings, both socket-weld and threaded.

API-598 - VALVE INSPECTION AND TESTING
Scope: This standard covers inspection, examination, supplementary examinations, pressure and test requirements for resilient-seated, nonmetallic-seated (for example, ceramic), and metal-to-metal-seated valves of the gate, globe, plug, ball, check, butterfly types.

API-607 - Fire Test for Soft Seated Quarter-turn Valves
Scope: This standard covers the requirements for testing and evaluating the performance of straightway, soft-seated quarter-turn valves when they are exposed to certain fire conditions defined

API STANDARDS

API-Spec 6A, Wellhead and Christmas Tree Equipment, 17th Edition, February 1996
(Includes Errata dated December 1996) Covers equipment utilized for pressure control systems for production of oil and gas. Specific equipment covered by this specification includes end and outlet connectors; ring gaskets; chokes; valves including surface and underwater safety valves; actuators; and wellhead and Christmas tree equipment (examples: casing head housings, casing and tubing head spools, hangers, connectors, fittings). Also covers repair and remanufacture of wellhead and Christmas tree equipment that was originally manufactured in accordance with the fifteenth or later edition of this specification. Since API Specification 6A is sent looseleaf, ring binders are available for purchase.

API-Spec 6AV1, Verification Test of Wellhead Surface Safety Valves and Underwater Safety Valves for Offshore Service, 1st Edition, February 1996
(Includes Errata dated December 1996) Establishes testing requirements to verify the design of surface safety valves (SSV) and underwater safety valves (USV), and SSV/USV actuators, manufactured in accordance with API Specification 6A. Includes requirements for verification testing of SSVs and USVs for two performance requirement levels.

API-Spec 6D, Pipeline Valves (Gate, Plug, Ball, and Check Valves), 21st Edition, March 1994
(Includes Supplement 2 dated December 1997) Covers flanged and butt-welding gate, plug, ball, and check valves. Clarifies the types, categories and bore sizes of valves covered; adjusts test and marking requirements accordingly; simplifies the dimensional table for gate valves; adds metric conversions of all dimensional tables; and includes other clarifications and updates.

API-Spec 6FA, Fire Test for Valves, 2nd Edition, February 1994
Covers the requirements for testing and evaluating the performance of API Spec 6A and Spec 6D valves when exposed to specifically defined fire conditions.

API-Spec 6FC, Fire Test for Valve With Automatic Backseats, 2nd Edition, February 1994
Covers the requirements for testing and evaluating the performance of API Spec 6A and Spec 6D valves with automatic backseats when exposed to specifically defined fire conditions.

API-Spec 6FD, Fire Test for Check Valves, 1st Edition, February 1995

Establishes the requirement for testing and evaluating the pressure containing performance of API Spec 6A and 6D check valves when exposed to fire. The performance requirements of this document are intended to establish standard limits of acceptability regardless of size or pressure rating.

API-Spec 14A, Subsurface Safety Valve Equipment, 9th Edition, December 1994
(Includes Supplement dated December 1997) Covers subsurface safety valves, safety valve locks, and safety valve landing nipples. Includes minimum acceptable standards for materials, manufacturing, and testing of both surface- and subsurface-controlled safety valves for three classes of service.


API-Std 553, Refinery Control Valves, 1st Edition, September 1998
This document provides recommended criteria for the selection, specification and application of piston and diaphragm actuated control valves. It also outlines control valve design considerations, discusses control valve sizing, noise, fugitive emissions, and defines types of commonly used control valves and their actuators.

API-Std 589, Fire Test for Evaluation of Valve Stem Packing, 2nd Edition, January 1993 (ANSI/API Std 589-1993)
Covers the requirements for testing valve stem packing and evaluating its performance when exposed to specifically defined fire conditions. Packing may be a combination or an arrangement of more than one material. The test procedure in this standard simulates circumstances that impose severe demands on valve stem packing. Purchasers may wish to establish more stringent requirements to meet their specific applications.

API-Std 590, Steel Line Blanks, 1st Edition, March 1985, Reaffirmed May 1995 (ANSI/API Std 590-1993)
Provides dimensions for operating line blanks in sizes NPS 1/2 through NPS 24 for installation between ANSI Bl6.5 flanges in the 150-, 300-, 600-, 900-, 1500-, and 2500-pound pressure classes. The dimensions given are suitable for blanks made of any of 10 different steel plate materials.

API-Std 594, Check Valves: Wafer, Wafer-Lug and Double Flanged Type, 5th Edition, November 1997 (ANSI/API Std 594-1993 )
This standard covers design, materials, face-to-face dimensions, pressure-temperature ratings, and examination, inspection, and test requirements for gray iron, ductile iron, steel, and alloy single and dual plate check valves. Valve configurations include wafer, wafer-lug, and double-flanged type with facings that will permit installation between ASME and MSS flanges that conform to the standards and specifications listed in the Refinery Service Valve Standards.

API- Std 599, Metal Plug Valves--Flanged and Welding Ends, 5th Edition, November 1994
A purchase specification that covers requirements for metal plug valves with flanged or butt-welding ends, and ductile iron plug valves with flanged ends, in sizes NPS 1 through NPS 24, which correspond to nominal pipe sizes in ASME B36.10M. Valve bodies conforming to ASME B16.34 may have flanged end and one butt-welding end. It also covers both lubricated and non-lubricated valves that have two-way coaxial ports, and includes requirements for valves fitted with internal body, plug, or port linings or applied hard facings on the body, body ports, plug, or plug port.

API-Std 600, Steel Gate Valves--Flanged and Butt-Welding Ends Bolted and Pressure Seal Bonnets, 10th Edition, February 1997
This standard is for the convenience of purchasers and manufacturers who order, fabricate, or install steel gate valves. Covers steel gate valves with flanged or butt-welding ends in sizes NPS1 through NPS 24.

API- Std 602 Compact Steel Gate Valves- Flanged, Threaded, Welding and Extended Body Ends, 6th Edition, June 1993
Covers threaded-end, socket-welding-end, butt-welding-end, and flanged-end compact carbon steel gate valves in sizes NPS 4 and smaller.

API-Std 603, Class 150, Cast, Corrosion-Resistant, Flanged-End Gate Valves, 5th Edition, July 1991, Reaffirmed November 1996 (ANSI/API Std 603-1993 )
This standard covers Class 150, cast, corrosion resistant, flanged-end gate valves in sizes NPS 1/2 through 12 for use in petroleum refinery piping systems. The valves are outside-screw-and-yoke (OS&Y) valves with rising stem, nonrising handwheel, bolted bonnet, integral seats in the body, raised-face end flanges, and various types of gates.

API-Std 608, Metal Ball Valves--Flanged, Threaded and Butt-Welding Ends, 2nd Edition, September 1995 (ANSI/API Std 608-1995 )
Covers Class 150 and Class 300 metal ball valves that have either butt-welding or flanged ends and are for use in on-off service.

API-Std 609, Butterfly Valves: Double Flanged, Lug- and Water-Type, 5th Edition, May 1997
Covers design, materials, face-to-face dimensions, pressure-temperature ratings, and examination, inspection, and test requirements for gray iron, ductile iron, bronze, steel, nickel-base alloy, or special alloy butterfly valves that provide tight shutoff in the closed position and are suitable for flow regulation.


API-RP 591, User Acceptance of Refinery Valves, 2nd Edition, February 1998
This recommended practice describes actions a purchaser can take to procure new valves that are required to be in accordance with the Refinery Service Value standards. The purchaser may find that the suggested actions also apply to valves manufactured to other specifications

API-RP 6AR, Repair and Remanufacture of Wellhead and Christmas Tree Equipment, 1st Edition, April 1994
Provides guidelines for the repair and remanufacture of safe, interchangeable wellhead and Christmas tree equipment. Includes recommendations for performance, design, materials, testing, inspection, welding, marking, handling, storing, and shipping. Contains guidelines for repair and remanufacture of equipment not originally manufactured to, or lacking traceability to verify, API Product Specification Levels specified in the 15th and later editions of API Spec 6A.

API-RP 14B, Design, Installation, Repair and Operation of Subsurface Safety Valve Systems, 4th Edition, July 1994
(Includes Errata dated June 1996) Covers procedures for design calculations, instructions for safe installation and guidelines for operating and testing to assure safe and efficient performance of subsurface safety valve systems (SSSVS), and covers repair and remanufacture of SSSV equipment.

API-RP 14H, Installation, Maintenance and Repair of Surface Safety Valves and Underwater Safety Valves Offshore, 4th Edition, July 1994
(Includes Errata dated September 23, 1996) Covers guidelines for inspecting, installing, maintaining, repairing, and operating of SSVs/USVs. Pages: 16.

ANSI/API STANDARDS

ANSI B16.104 Specification

Control Valve Seat Leakage Classifications
(In accordance with ANSI B16.104)
Leakage Class Designation Maximum Leakage Allowable Test Medium Test Pressure Testing Procedures Required for Establishing Rating
I XXX XXX XXX No test required provided user and supplier so agree
II 0.5% of rated capacity Air or water at 50-125 F (10-52C) 45-60 psig or max. operating differential whichever is lower Pressure applied to valve inlet with outlet open to atmosphere or connected to a low head loss measuring device full normal closing thrust provided by actuator.
III 0.1% of rated capacity As above As above As above
IV 0.01% of rated capacity As above As above As above
V 0.0005 ml per minute of water per inch of port diameter per psi differential Water at 50to125F (10to52C) Max service pressure drop across valve plug, not to exceed ANSI body rating. (100 psi pressure drop minimum) Pressure applied to valve inlet after filling entire body cavity and connected piping with water and stroking valve plug closed. Use net specified max actuator thrust, but no more, even if available during test. Allow time for leakage flow to stabilize.
VI Not to exceed amounts shown in following table based on port diameter. Air or nitrogen at 50 to 125 F (10to52C) 50 psig or max rated differential pressure across valve plug whichever is lower. Actuator should be adjusted to operating conditions specified with full normal closing thrust applied to valve plug seat. Allow time for leakage flow to stabilize and use suitable measuring device.
Control Valve Seat Leakage Classifications
(In accordance with ANSI B16.104)
NOMINAL PORT DIAMETER NOMINAL PORT DIAMETER LEAK RATE LEAK RATE
Inches Millimeters ml per Minute Bubbles / minute*
1 25 0.15 1
1-1/2" 38 0.3 2
2 51 0.45 3
2/1/02 64 0.6 4
3 76 0.9 6
4 102 1.7 11
6 152 4 27
8 203 6.75 45
* See complete ANSI specification bulletin B16.104

ANSI/API 526-1984 (R1992)
Title: Flanged Steel Safety Relief Valves
Abstract: Describes a purchase specification for flanged steel safety-relief valves.

ANSI/API 527-1991
Title: Seat Tightness of Safety Relief Valves
Abstract: Describes a method for determining seat tightness of safety relief valves as covered in ANSI/API 526-1984, Flanged Steel Safety Relief Valves for Use in Petroleum Refineries. The maximum acceptable leakage rates are defined for commercial safety relief valves with metal-to-metal seats for set pressures up to 6000 pounds per square inch gage (41 megapascals).

ASME

ASME B16.10-1992
Title: Face-to-Face and End-to-End Dimensions of Valves
Abstract: This standard covers face-to-face and end-to-end dimensions of straightway valves, and center-to-face and center-to-end dimensions of angle valves. Its purpose is to assure installation interchangeability for valves of a given material, type, size, rating class, and end connection.

ASME Y32.2.3-1949 (R1994)
Title: Graphical Symbols for Pipe Fittings, Valves and Piping
Abstract: Covers graphical symbols for use on drawings.

ASME/BPE-1997 Bioprocessing Equipment
Scope: The standard is intended for design, materials, construction, inspection and testing of vessels, piping and related accessories such as pumps, valves, and fittings for use in the biopharmaceutical industry.

ANSI/ISA®

ANSI/ISA® S75.01-1985 (R1995)
Title: Flow Equations for Sizing Control Valves
Abstract: Establishes equations for predicting the flow of compressible or incompressible fluids through control valves. May not be applicable to mixed phase flow, dense slurries, dry solids, or non-Newtonian liquids.

ANSI/ISA® S75.02-1996
Title: Control Valve Capacity Test Procedures
Abstract: Provides a procedure for testing control valve capacity and related flow coefficients for both compressible and incompressible fluids. This standard also provides a procedure to evaluate the major data.

ANSI/ISA® S75.03-1984
Title: Valve Bodies, Face-to-Face Dimensions for Flanged Globe Style Control
Abstract: Applies to flanged control valves sizes 1/2-inch through 16 inches having top, top and bottom, port, or cage guiding. This standard aids users in their piping design by providing ANSI Class 125 flat face and ANSI Classes 150, 250, 300, and 600 raised face flanged control valve dimensions without giving special consideration to the manufacturer or equipment to be used.

ANSI/ISA® S75.04-1995
Title: Face-to-Face Dimensions of Flangeless Control Valves (ANSI Classes 150, 300, and 600)
Abstract: Applies to flangeless control valves, sizes 3/4 through 16 inches for ANSI Classes 150 through 600. The purpose of this standard is to aid users in their piping designs for flangeless control valves without giving special consideration to the equipment manufacturer to be used. This standard applies to flangeless ball control valves utilizing a full ball or a segment of a ball and other rotary-stem or sliding-stem flangeless control valves. This standard does not apply to weld-end valves, butterfly valves, or other rotary stem valves that may be covered by other standards.

ANSI/ISA® S75.05-1983
Title: Control Valve Terminology

ANSI/ISA® S75.08-1985
Title: Installed Face-to-Face Dimensions for Flanged Clamp or Pinch Valves
Abstract: Applies to control valves, sizes 1 through 8 inches, incorporating clamp or pinch elements, and provides installed face-to-face dimensions for control valves which have flanges that mate with the Class 125 (PN20) flanges covered in ANSI B16.1-1975, and/or the Class 150 (PN20) flanges covered in ANSI B16.5-1981.

ANSI/ISA® S75.11-1985 (R1991)
Title: Control Valves, Inherent Flow Characteristic and Rangeability of
Abstract: Defines typical control valve inherent flow characteristics and inherent rangeability by manufacturers, and establishes criteria for adherence to manufacturer-specified flow characteristics.

ANSI/ISA® S75.12-1993
Title: Face-to-Face Dimensions for Socket Weld-End and Screwed-End Globe-Style Control Valves (ANSI Classes 150, 300, 600, 900, 1500, and 2500)

ANSI/ISA® S75.14-1984
Title: Face-to-Face Dimensions for Buttweld-End Globe-Style Control Valves
Abstract: Applies to butt-end globe-style control valves, sizes 1/2 inch through 8 inches, having top and cage guiding. The purpose of this standard is to aid users in their piping designs by providing ANSI Class 450 buttweld-end control valve dimensions, without giving special consideration to the equipment manufacturer to be used. ANSI/ISA® S75.15-1993
Title: Face-to-Face Dimensions for Buttweld-End Globe-Style Control Valves (ANSI Classes 150, 300, 600, 900, 1500, and 2500)

ANSI/ISA® S75.16-1993
Title: Face-to-Face Dimensions for Flanged Globe-Style Control Valve Bodies (ANSI Classes 900, 1500, and 2500) ANSI/ISA® S75.17-1991 Title: Control Valve Aerodynamic Noise Prediction Method

ANSI/ISA® S75.19-1995
Title: Hydrostatic Testing of Control Valves Abstract: Establishes requirements and definitions for standard hydrostatic shell testing of control valves by valve manufacturers to prove the structure integrity and leak tightness of the pressure-retaining parts.

ANSI/ISA® S75.07-1987
Title: Laboratory Measurement of Aerodynamic Noise Generated by Control Valves Abstract: This standard provides a procedure for testing, measuring, and reporting the aerodynamic noise-generating characteristics of a control valve and its associated piping.

IEC

IEC 60534-6 Ed. 1.0 b:1985
Title: Industrial-process control valves. Part 6: Mounting details for attachment of positioners to control valve actuators
Abstract: Permits a variety of positioning devices which respond to a linear motion to be mounted on the actuator of a control valve, either directly or by employing an intermediate mounting bracket. The standardized mounting applies to positioners which are mounted on the side of the actuator, to those actuators which have a travel of 100 mm or less, and is designed to cover three basic types of actuator design: a)those with some form of cast or fabricated yoke to connect the actuator power unit to the valve; b)those which use some form of central tube yoke to connect the actuator power unit to the valve; c)those in which the yoke incorporates two or more columns or pillars to connect the actuator power unit to the valve.

IEC 60534-6-1 Ed. 1.0 b:1997
Title: Industrial-process control valves - Part 6: Mounting details for attachment of positioners to control valves - Section 1: Positioner mounting on linear actuators
Abstract: Intended to permit a variety of positioning devices, which respond to a linear motion, to be mounted on the actuator of a control valve, either directly or by employing an intermediate mounting bracket. Applicable where interchangeability between actuators and positioners is desired.

LINKS

*Excerpt from the soon-to-be-released book Valve and Actuator Technology II by Wayne Ulanski.
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