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.
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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.
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Sleeve Material Physical Properties
ASTM
TestProperty
Polye-
thyleneMylar Nomex Phenolic Silicone
Glass
G-7*Epoxy
Glass
G-10Epoxy
Glass
G-111-piece
sleeve &
washerD149 Volts/mil 400 4000 400 400 350 400 400 1,200 D695 Compressive
strength psiN/A N/A N/A N/A N/A N/A N/A 18,000 D229 % water
absorption0.01 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
+225Cryogenic
to +450Cryogenic
to +280Cryogenic
to +320-30 to
+180Operating
temp ºC-34 to
+82-59 to
+149-54 to
+232-29 to
+107Cryogenic
to +232Cryogenic
to +138Cryogenic
to +160-34 to
+82D790 Flexural
strength psi7,000 13,000 20,000 16,000 20,000 55,000 55,000 1,400 Cut-thru resis-
tance ft-lbs1,800 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 PropertiesASTM
TestProperty Glass clad
phenolicHi-temp
Phenolic
G-3Silicone
Glass
G-7*Epoxy
Glass
G-10Epoxy
Glass
G-111-piece
sleeve &
washerD149 Volts/mil 500 550 350-400 550 550 1,200 D695 Compressive
strength psi33,000 50,000 40,000 50,000 50,000-
80,00018,000 D229 % water
absorption1.6 0.7 0.07 0.10 0.10 0.22 Operating
temp ºF-65 to
+300ºFº-65 to
+392ºFCryogenic
to +450ºFCryogenic
to +280ºFCryogenic
to +350ºF-30 to
+180ºFOperating
temp ºC-54 to
+149ºC-54 to
+200ºC-Cryogenic
to +232ºCCryogenic
to +138ºCCryogenic
to +177ºC-34 to
+82ºC* = G-7 material should not be used with hydrocarbons, not even trace amounts.