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GPT Flange isolation kits are available for all flange sizes, types, pressure ratings and materials. Each kit is individually and securely packed in a reinforced corrugated cardboard box, which is clearly labeled as to its contents for convenience in warehousing and field use. Very large diameter gaskets are packaged separately from the sleeves and washers for convenience in storing and handling. Each gasket is labeled with:
Materials (Retainer Material or Retainer / Seal Element Combination)
Pipe Size
ANSI Class
Date of Manufacture
Type Flange (Weld Neck or Slip-on)
Sleeves and washers are enclosed in a strong polyethylene bag to eliminate any possibility of loss. A chart showing the recommended sequence for tightening flange bolts is also included with each kit, as well as with each individual gasket.
Common LineBacker® & GasketSeal® Sealing Gasket Physical Properties
ASTM Test
Property
Plain Phenolic
Neo-faced Phenolic
Hi-temp Phenolic G-3
Silicone Glass G-7*
Epoxy Glass G-10
Epoxy Glass G-11
D149
Dielectric strengths, Volts/mil
500
500
550
350-400
550
550
D695
Compressive strength, psi
25,000
25,000
50,000
40,000
50,000
50,000+
D229
Water absorption, %
1.6
1.6
0.7
0.07
0.10
0.10
D257
Insulating Resistance, Meg Ohms
40,000
40,000
46,000
2,500
200,000
200,000
D790
Flexural strength, psi
22,500
22,500
60,000
27,000
60,000
75,000+
D785
Hardness Rockwell "M"
85
85
115
105
115
115
D256
IZOD Impact, Strength ft-lbs/inch
1.2
1.2
12.0
8.0
14.0
12.0
D732
Shear strength, psi
10,000
10,000
18,000
20,000
22,000
22,000
D229
Operating temp, ºF
-65 to +220
-65 to +175
-65 to +392
Cryogenic to +450
Cryogenic to +280
Cryogenic to +350
Operating temp, ºC
-54 to +104
-54 to +79
-54 to +200
-Cryogenic to +232
Cryogenic to +138
Cryogenic to +177
* = G-7 material should not be used with hydrocarbons, not even trace amounts.
Seal Element Temperature Limits
Nitrile
Viton
Teflon
Neoprene
EPDM
-65 to +250°F
-20 to +350°F
Cryogenic to +450°F
-40 to +175°F
-65 to +300°F
-54 to +121°C
-29 to +177°C
Cryogenic to +232°C
-40 to +79°C
-54 to +149°C
Consider both retainer and seal element temperature limits together for GasketSeal® and LineBacker® Sealing Gaskets.
Single washer set flange isolation kits include the following items for each bolt:
One - 1/8" thick steel washer
One - Isolating washer
One - Isolating sleeve
Application Considerations: In buried applications, single washer configurations may be used to allow the Cathodic Protection (CP) current to reach the nuts and bolts. If desired, nuts on the opposite side of the cathodically protected flange may be included as part of the CP system.
Double Washer Set
Double washer set flange isolation kits include the following components for each bolt:
Two - 1/8" thick steel washers
Two - Isolating washers
One - Full length isolating sleeve
Application Considerations: Double washer configurations may be used for added protection against the possibility of "shorting out" the nuts and bolts. In addition, double washer sets electrically isolate the nuts and bolts from both flanges.
One-Piece Sleeve and Washer Sets
One-piece sleeve and washer set flange isolation kits include the following items for each bolt:
Two - 1/8" thick steel washers
One - One-piece Isolating sleeve
Application Considerations: Easier to install, one-piece sleeves also allow the inspector a visual indication of sleeve usage. Due to the relatively low compressive strength of this material, its use is not recommended for high pressure or large diameter flanges that require high torque loads.
Flange Isolation Kit Specification Materials for flange isolation kits on pipes containing water, aqueous fluids or natural gas (up to 220°F, 104°C) shall consist of the following components:
Isolating and Sealing Gasket One full-faced isolating and sealing gasket, LineBacker Sealing Gasket - Type "E", 1/8" thick, phenolic retainer containing a precision tapered groove to accommodate the controlled compression of a nitrile quad-ring sealing element. Sealing element placement shall accommodate either flat, raised or RTJ face flanges. The quad-ring seal shall be pressure energized. The phenolic retainer shall have a 500 volts/mil dielectric strength and a minimum 25,000 psi compressive strength. The full faced flange isolating gasket shall be 1/8" less in I.D. than the I.D. of the flange in which it is installed.
Full Length Bolt Isolating Sleeves One full length Mylar sleeve (extending half way into both steel washers) for each flange bolt. The Mylar shall be a 1/32 inch thick tube with a 4000 volts/mil dielectric strength and water absorption of 0.8% or less.
Washers Two, 1/8 inch thick, glass clad phenolic isolating washers for each bolt. Their compressive strength shall be 33,000 psi, dielectric strength 500 volts/mil and water absorption 1.6% or less. Two, 1/8 inch thick steel washers for each bolt. The I.D. of all washers shall fit over the isolating sleeve and the steel and isolating washers shall have the same I.D. and O.D.
Quality Flange isolating kits shall be manufactured at a facility that has a registered ISO 9001:2000 Quality Management System. Submittals shall include copy of valid registration.
Top of the Line
Flange Isolation Kit Specification Materials for flange isolation kits on pipes containing natural gas, oil and aqueous fluids (up to 280°F, 138°C) shall consist of the following components:
Isolating and Sealing Gasket One full faced isolating and sealing gasket, LineBacker Sealing Gasket - Type "E", 1/8" thick, G-10 retainer containing a precision tapered groove to accommodate the controlled compression of a Teflon (or Viton) quad-ring sealing element. Sealing element placement shall accommodate either flat, raised face or RTJ flanges. The quad-ring seal shall be pressure energized. The G-10 retainer shall have a 550 volts/mil dielectric strength and a mini-mum 50,000 psi compressive strength. The full faced flange isolating gasket shall be 1/8" less in 1.D. than the I.D. of the flange in which it is installed.
Full Length Bolt Isolating Sleeves One full length G-10 sleeve (extending halfway into both steel washers) for each flange bolt. The G-10 shall be a 1/32 inch thick tube with a 400 volts/mil dielectric strength and water absorption of 0.10% or less.
Washers Two, 1/8 inch thick, G-10 isolating washers for each bolt. Their compressive strength shall be 50,000 psi, dielectric strength 550 volts/mil and water absorption 0.10% or less. Two, 1/8 inch thick zinc plated, hot rolled steel washers for each bolt. The I.D. of all washers shall fit over the isolating sleeve and both the steel and isolating washers shall have a same I.D. and O.D.
Quality Flange isolating kits shall be manufactured at a facility that has a registered ISO ISO 9001:2000 Quality Management System. Submittals shall include copy of valid registration.
Single Washer Set
Double Washer Set
One-Piece Sleeve and Washer Sets
Stelth 3 Portable Reference Electrodes by Borin Mfg.
