Flange Protection
PSI Isolating Gasket Types and Styles
Type “E” Gaskets
Type “E” Gaskets extend to the outside diameter of the flange. They feature precision located bolt holes, to automatically center the gasket, and offer maximum protection against foreign material “shorting-out” the flange.
Type “E” gaskets may be ordered in anyone of the
Following configurations:
• LineBacker Sealing Gaskets
• GasketSeal Sealing Gaskets
• Rubber Faced Phenolic Gaskets
• Plain Phenolic Gaskets
• Red Devil Gaskets
• Yellow Jacket Gaskets
• Teflon Gaskets
When configured as a LineBacker Sealing Gasket, the sealing element may be positioned anywhere between the
I.D. of the gasket and I.D. of the bolt circle.
Type “F” Gaskets
Type “F” Gaskets are made to fit within the bolt hole circle of the flange. The O.D. of the gasket extends out to the 1.0. of the bolt hole circle for good protection against foreign material “shorting-out” the flange. When configured as a LineBacker Sealing Gasket, the sealing element may be positioned anywhere between the 1.0. and 0.0. of the gasket. Type “F” gaskets may be ordered in anyone of the
Following Configurations:
• UneBacker Sealing Gaskets
• GasketSeal Sealing Gaskets
• Rubber Faced Phenolic Gaskets
• Plain Phenolic Gaskets
• Red Devil Gaskets
• Yellow Jacket Gaskets
• Teflon Gaskets
When configured as a LineBacker Sealing Gasket, the sealing element may be positioned anywhere between the I.D. of the gasket and 1.0. of the bolt circle.
Type “D” Gaskets
Type “0” Gaskets are available for RTJ flanges but the LineBacker
Sealing Gasket is an excellent alternative to “0” gaskets because the
sealing element may be positioned anywhere between the 1.0. of the
gasket and 1.0. of the ring groove.
PSI Isolating Gaskets – Standard 1/8″ Thick
GasketSeal & sealing gaskets are considered one of the most effective methods for sealing and isolating flanges of all types. The gasket consists of two molded semi “0” rings (with precise crown tovoid ratio) mounted in grooves on opposite sides of an isolating retainer.
While maintaining all the advantages of a full “0” ring seal, the semi “0” ring seal eliminates the need for a sealing groove in the flange face to reduce problems associated with alignment. GasketSeal gaskets are self energizing with theoretical near zero “m” and ‘y” factors resulting in effecting a positive seal without excessive bolt loads required with
flat gaskets. GasketSeal sealing gaskets are available in a wide variety of retainer and sealing element combinations for matching
gaskets to service and environmental conditions. Refer to the chart for the GasketSeal sealing gasket temperature ranges and material compatibilities.
LineBacker Sealing Gaskets
LineBacker sealing gaskets utilize a patented rectangular sealing element, referred to as a “quad” ring, in combination with a unique groove design to effectively seal and isolate flanges of all types. With the unique “quad” ring design, elastic memory
is provided for elastomers not normally associated with this characteristic. Materials such as AFLAS, TFE (Teflon) and KALREZ may therefore be used as sealing elements which dramatically increases the options available for matching gasket materials to
service and environmental conditions. This greater variety of materials also provides excellent temperature and chemical range
compatibility. LineBacker sealing gaskets are self energizing with theoretical near zero “m” and ‘}t” factors resulting in effecting a positive seal without excessive bolt loads required with flat gaskets. Refer to chart for Linebacker sealing gasket temperature range and material compatibilities.
Rubber Faced Phenolic Gaskets Flat
Rubber Faced Phenolic gaskets have been used as standard “flat” isolating gaskets in the oil and gas industries for many years. Soft neoprene rubber sheets are factory applied to both sides of a laminated phenolic retainer providing an effective sealing surface. The temperature limit of these gaskets is approximately + 1750 F. (80 0 C.). Note: Due to improved sealing characteristics and retainer/seal element options, LineBacker or GasketSeal sealing gaskets should be considered in lieu of rubber faced phenolic gaskets whenever possible. Flat gaskets are used in special applications.
Flat Gaskets
Flat gaskets are used in special applications such as elevated temperatures that often require materials such as Red Devil or Yellow Jacket. Please contact a PSI representative for additional information on available options.
| Medium | Retainer | Seal | Sleeve | Washer | Temp. Range of °F | Temp. Range °C |
| Acetone | Phenolic | EPDM | Mylar | Phenolic | +32 to +80 | 0 to +27 |
| Ethanol | G-10 | EPDM | Mylar | G10 | +32 to +100 | 0 to +38 |
| Water (Sea) | G-10 | EPDM | Mylar | G-10 or Phenolic | +32 to +280 | 0 to +138 |
| Water (hot) | G-10 | EPDM | Mylar | G-10 | +175 to +280 | +79 to +138 |
| Water (Potable) | G-10 | EPDM | Mylar | G-10 or Phenolic | +32 to +280 | 0 to +138 |
| Steam | Consult | Factory | Consult | Factory | ||
| Caustic Soda (NaOH) | Consult | Factory | Consult | Factory | ||
| Carbon Dioxide | G-10 | Nitrile | Mylar | G-10 | +32 to +150 | 0 to +66 |
| Gas, Natural | Phenolic | Nitrile | Mylar | Phenolic | -20 to +220 | -40 to +104 |
| Air | G-10 | Nitrile | Mylar | Phenolic | -40 to +225 | -40 to +107 |
| Nitrogen | Phenolic | Nitrile | Mylar | Phenolic | -20 to +280 | -40 to +104 |
| Hydrogen | G-10 | Nitrile | Mylar | G-10 | -20 to +225 | -40 to +121 |
| Propane | G-10 | Nitrile or Teflon | G-10 | G-10 | +32 to +80 | 0 to +27 |
| MTBE | G-10 | Special Nitrile | G-10 | G-10 | -40 to +220 | oto +27 |
| Gasoline | G-10 | Teflon | Mylar | G-10 | -40 to +250 | -54 to +107 |
| Ammonia Dry | G-10 | Teflon | Mylar | G-10 | -65 to +220 | -54 to +104 |
| Cryogenic | G-10 | Teflon | G-10 | G-10 | -300 to +280 | -184 to +138 |
| LNG | G-11 | Teflon | G-10 | G-10 | -20 to +80 | -184 to +38 |
| Ammonia (Wett).. | G-10 | Teflon | Mylar | G-10 | +32 to +100 | 0 to +38 |
| Methanol | G-10 | Teflon | Mylar | G-10 | +32 to +80 | 0 to +38 |
| Ethylene (Ethene) | G-10 | Teflon | G-10 | G-10 | +32 to +80 | 0 to +27 |
| Bleach | G-10 | Teflon | Mylar | G-10 | +32 to +80 | 0 to +27 |
| Sulphur (Molten) | G-10 | Teflon | G-10 | G-10 | +32 to +280 | 0 to +138 |
| Oxygen” | G-10 | Teflon | G-10 | G-10 | +32 to +80 | -54 to +121 |
| Pentane | G-10 | Teflon | G-10 | G-10 | +32 to +80 | 0 to +27 |
| Butylene (Butidiene) | G-10 | Teflon | G-10 | G-10 | +32 to +100 | 0 to +38 |
| Styrene | G-10 | Teflon | G-10 | G-10 | +32 to +80 | 0 to +27 |
| White Liquor | G-10 | Teflon | G-10 | G-10 | +80 to +280 | +27 to +138 |
| Spent Liquor | G-10 | Teflon | G-10 | G-10 | +32 to +100 | 0 to +27 |
| Mercaptan | G-10 | Teflon | G-10 | G-10 | +32 to +100 | -29 to +27 |
| Sewage | G-10 | Viton | Mylar | G-10 | -20 to +280 | 0 to +38 |
| Propylene | G-10 | Viton | G-10 | G-10 | +32 to +80 | -29 to +138 |
| Oil, Crude | G-10 | Viton | Mylar | G-10 | -65 to +250 | -29 to +138 |
| Jet Fuel | G-10 | Viton | Mylar | G-10 | -300 to +100 | -29 to +107 |
| Gas, Sour | G-10 | Viton | Mylar | G-10 | -65 to +225 | -29 to +104 |
| Fuel Oil | G-10 | Viton | Mylar | Phenolic | -20 to +280 | -29 to +138 |
| Tolulene | G-10 | Viton or Teflon | G-10 | G-10 | +32 to +150 | 0 to +66 |
•• = These are organic materials that will feed a fire if a leak occurs and an ignition source exists.
… = Ammonia (wet) – Data to +100°F (+38°C) only (same materials as dry).
Sleeves and Washers
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/studs within standard size bolt holes, PSI isolating sleeves have a wall thickness of 1/32″ (0. 79mm) and are used with separate isolating and steel washers. They are available for standard American bolt sizes from 1/2″ (12.7mm) to 3-1/2″ (88.9mm) as well as metric bolt sizes from 12mm and larger. Isolating Washers – Standard 118″ Thick
Isolating Washers – Standard 118″ Thick
Isolating washers 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.
PSI isolating washers are available for bolt sizes
from 1/2″ (12.7mm) through 3-1/2″ (88.9mm)
and are made to fit over the isolating sleeves.
One-piece Sleeves and Washers
Molded from acetal resin and available for bolt diameters from 1/2″ to 1-1/2″ (12.7 to 38.1mm), 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.
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.
Flange Isolation Kits
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
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.
Flange Isolation Kits
Single Washer Set
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.
Typical Specifications
General/Economical
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 EPDM 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 1.0. than the 1.0. 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 1.0. of all washers shall fit over the isolating sleeve and the steel and isolating washers shall have the same 1.0. and 0.0.
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 minimum 50,000 psi compressive strength. The full faced flange isolating gasket shall be 1/8″ less in 1.0. than the 1.0. of the flange in which it is installed.
Full Length Isolating Sleeves One full length G-10 sleeve (extending half way 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-1O isolating washers for each bolt. Their compressive strength shall be 50,000 psi, dielectric strength 550 volts/mil and water absorption O. 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 1.0. and 0.0. Two, 1/8 inch thick, G-1O isolating washers for each bolt. Their compressive strength shall be 50,000 psi, dielectric strength 550 volts/mil and water absorption O. 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 1.0. and 0.0.
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
| ANSI
Class |
Gasket
Type |
GasketSeal/LineBacker Sealing Gaskets
▾ |
Washers | Washer Materials | Sleeve | Type |
| 150#
300# 400# 600# 900# 1500# 2500# |
E= With Holes
F= Ring (No Bolts Holes) D= For RTJ Flanges |
GS= GasketSeal
LB= LineBacker NP= Rubber Faced Phenolic PP= Plain Phenolic RD= Red Devil YJ= Yellow Jacket TF= Teflon D= Phenolic D Ring |
Retainer Phenolic G-3 G-7 G-10 G-11 |
Seal Element
Neoprene Nitrile Viton EPDM Teflon(LB ony) |
Poly= Poly- Ethylene
Mylar Nomex Phenolic G-7 G-10 G-11 |
W= Weld Neck
S= Slip On R=RTJ BX= API BX RX= API RX O= other Denote Specs and Table |
