Isolating Sleeves & Washers, by GPT

Isolating sleeves fit over standard size flange bolts. Isolating washers fit over isolating sleeves. Also available: one-piece sleeves & washers.
  • GPT Isolating Sleeves

    Isolating sleeves are available in the following materials:

    • Mylar
    • Polyethylene
    • Phenolic
    • Nomex®
    • G-7 Silicon Glass
    • G-10 Epoxy Glass
    • G-11 Epoxy Glass

    Designed to easily fit over standard size flange bolts and studs within standard size bolt holes, GPT isolating sleeves have a wall thickness of 1/32" (0.79 mm) and are used with separate isolating and steel washers. They are available for standard American bolt sizes from 1/2" (12.7 mm) to 3-1/2" (88.9 mm) as well as metric bolt sizes from 12 mm and larger.

    GPT Isolating Washers

    Isolating washers have a standard thickness of 18" and are available in the following materials:

    • High Strength Glass Clad Phenolic
    • G-3 High Temp. Phenolic
    • G-7 Silicon Glass
    • G-10 Epoxy Glass
    • G-11 Epoxy Glass

    Designed to provide tough, positive isolation. GPT isolating washers are available for bolt sizes from 1/2" (12.7 mm) through 3-1/2" (88.9 mm) and are made to fit over the isolating sleeves.

    GPT One-piece Sleeves & Washers

    Molded from acetal resin and available for bolt diameters from 1/2" to 1-1/2" (12.7 to 38.1 mm), one-piece sleeves and washers are structurally tough but limited to applications where the flange temperature does not exceed +180°F (+80°C) and compressive loads do not exceed 18,000 psi. They are generally used as single washer sets because they're molded to specific lengths and, in many instances, are longer than the thickness of a single flange. A washer centering ring positions the steel washer on the unit properly to avoid uneven pressures on the washers. G-10 one-piece sleeve / washer assemblies are available for additional strength and convenience.

    PSI Steel Washers

    Steel washers are designed to fit over the isolating sleeve or the retainer ring on the one-piece sleeves and washers. The outside diameter is sized to fit within the bolt facing on ANSI standard flanges. They are made of 1/8" (3.2mm) thick plated hot-rolled steel.


  • Sleeve Material Physical Properties

    ASTM
    Test

    Property

    Polye-
    thylene
    Mylar Nomex Phenolic Silicone
    Glass
    G-7*
    Epoxy
    Glass
    G-10
    Epoxy
    Glass
    G-11
    1-piece
    sleeve &
    washer
    D149 Volts/mil 400 4000 400 400 350 400 400 1,200
    D695 Compressive
    strength psi
    N/A N/A N/A N/A N/A N/A N/A 18,000
    D229 % water
    absorption
    0.01 0.8 N/A 1.6 0.10 0.10 0.10 0.22
    Operating
    temp ºF
    -30 to
    +180
    -75 to
    +300
    -65 to
    +450
    -20 to
    +225
    Cryogenic
    to +450
    Cryogenic
    to +280
    Cryogenic
    to +320
    -30 to
    +180
    Operating
    temp ºC
    -34 to
    +82
    -59 to
    +149
    -54 to
    +232
    -29 to
    +107
    Cryogenic
    to +232
    Cryogenic
    to +138
    Cryogenic
    to +160
    -34 to
    +82
    D790 Flexural
    strength psi
    7,000 13,000 20,000 16,000 20,000 55,000 55,000 1,400
    Cut-thru resis-
    tance ft-lbs
    1,800 3,500 4,000 No test No test 16,000 No test 3,400
    * = G-7 material should not be used with hydrocarbons, not even trace amounts.
     
    1/8" Washer Material Physical Properties
    ASTM
    Test
    Property Glass clad
    phenolic
    Hi-temp
    Phenolic
    G-3
    Silicone
    Glass
    G-7*
    Epoxy
    Glass
    G-10
    Epoxy
    Glass
    G-11
    1-piece
    sleeve &
    washer
    D149 Volts/mil 500 550 350-400 550 550 1,200
    D695 Compressive
    strength psi
    33,000 50,000 40,000 50,000 50,000-
    80,000
    18,000
    D229 % water
    absorption
    1.6 0.7 0.07 0.10 0.10 0.22
    Operating
    temp ºF
    -65 to
    +300ºFº
    -65 to
    +392ºF
    Cryogenic
    to +450ºF
    Cryogenic
    to +280ºF
    Cryogenic
    to +350ºF
    -30 to
    +180ºF
    Operating
    temp ºC
    -54 to
    +149ºC
    -54 to
    +200ºC
    -Cryogenic
    to +232ºC
    Cryogenic
    to +138ºC
    Cryogenic
    to +177ºC
    -34 to
    +82ºC
    * = G-7 material should not be used with hydrocarbons, not even trace amounts.