A Jacketed gasket features an inner soft material core and an outer metallic shell. The inner filler material provides resilience to the gasket, whereas the metal jacket protects the inner core and withstands the pressure, the temperature, and the corrosion of the sealed device (heat exchanger, pump, or valve). Jacketed gaskets require a smooth flange surface finish, high bolt loads, and flat flanges to seal effectively. A double jacketed gasket has two different layers for the metal shell, i.e. an inner overlap and an outer overlap metal jacket.

 

The size range and thickness tolerances for this type of gaskets are defined by ASME B16.21:

  • OD: Less than 5,000mm
  • Thickness: 2~8mm with tolerance +0.03 inch. to -0.000 inch (+0.8mm, -0.0mm)

Jacketed gaskets are not generally used for flanged connections, differently from Soft, Spiral Wound, and Kammprofile Gaskets.

 

JACKETED GASKET MATERIALS

METAL JACKET

The table shows the most common metals used for jacketed gaskets and the recommended temperature range:

Jacket Materials Hardness HB Temp.℃
Carbon Steel 90 -60~+450
304 (L) 130 -270~+550
316 (L) 130 -270~+550
321 130 -270~+550
Monel 110 -60~+500
Inconel 90 -60~+600
AL 30 -250~+300
CU 80 -250~+400

 

SOFT FILLER MATERIALS

  • Non-Asbestos Millboard
  • CAF
  • Rubber
  • Woven Asbestos (may be forbidden in some countries)
  • PTFE
  • ‘Graflex’ Exfoliated Graphite
  • Non-asbestos

 

JACKETED GASKET DESIGNS

The two main types of metal jacketed gasket are the single jacket and the double jacket type. A multitude of designs originates from this basic classification as shown in the image below.

Double Jacketed Corrugated Double Jacketed Corrugated
— soft filler

Reduced contact area, enhances compression characteristics, suitable for uneven flanges.
Double Jacketed Corrugated — metal filler Double Jacketed Corrugated
— metal filler

Usually stainless outer casing with soft iron filler ring.
Core material available St. St. -304.316L.321
Soft iron, Monel, Inconel
Single Corrugated — asbestos rope filler Single Corrugated
— asbestos rope filler

Typically used on very poor or pitted flanges, low bolt loading requirement.
Metal Jacket Laminates — soft filler Metal Jacket Laminates
— soft filler

Combines flexible graphite with stainless steel core material
Solid metal ring machined Solid metal ring machined on each contact face to provide a serrated surface finish covered with Graphite.
PTFE Nonas or Asbestos.
Double Jacketed – soft filler Double Jacketed – soft filler
Used on high-temperature pressure applications or where corrosion problems may exist
Single Jacketed – metal filler – partly enclosed Single Jacketed – metal filler
– partly enclosed

Very seldom used, old design. Used in applications where poor or pitted flanges exist on one facing.
Single Jacketed – Soft filler – partly enclosed Single Jacketed – Soft filler
– partly enclosed

Used on narrow flanges
Single Jacketed – Soft filler – open outside edge Single Jacketed – Soft filler
– open outside edge

Used in narrow flanges, protection of filler cleared for by casing
Single Corrugated – no filler Single Corrugated – no filler
Used mainly in valve applications, small recess gap. Sometimes referred to as Taylor ring.

 

JACKETED GASKET DIMENSIONS (ASME B16.5 FLANGES)

Jacketed Gasket Dimensions Class 150-400

Jacketed gasket dimension
Jacketed gasket dimension
NPS d1 d2
150 300 400
1/2 23.8 44.5 50.8 50.8
3/4 31.8 54 63.5 63.5
1 36.5 63.5 69.9 69.9
46 73 79.4 79.4
52.4 82.6 92.1 92.1
2 73.2 101.6 108 108
85.9 120.6 127 127
3 107.8 133.4 146.1 146.1
4 131.8 171.5 177.8 174.7
5 152.4 193.8 212.8 209.5
6 190.5 219.1 247.7 244.5
8 238.3 276.3 304.8 301.7
10 285.8 336.6 358.8 355.6
12 342.9 406.4 419.1 415.9
14 374.7 447.7 482.6 479.5
16 425.5 511.2 536.6 533.4
18 489 546.1 593.7 590.6
20 533.4 603.3 650.9 644.5
24 641.4 714.4 771.6 765.3
NPS d1 150 300 400

 

Jacketed Gasket Dimensions Class 600-2500

Jacketed gasket dimension

NPS d1 d2
600 900 1500 2500
1/2 23.8 50.8 60.4 60.4 66.8
3/4 31.8 63.5 66.7 66.7 73.1
1 36.5 69.9 76.2 76.2 82.5
46 79.4 85.8 85.8 101.6
52.4 92.1 95.3 95.3 114.3
2 73.2 108 139.7 139.7 143
85.9 127 161.9 161.9 165.1
3 107.8 146.1 165.1 171.5 193.8
4 131.8 190.5 203.2 206.5 231.9
5 152.4 238.2 244.6 250.9 276.3
6 190.5 263.6 285.8 279.4 314.5
8 238.3 317.5 355.6 349.3 384.3
10 285.8 396.9 431.8 431.8 473.2
12 342.9 454.1 495.3 517.6 546.1
14 374.7 489 517.6 574.7
16 425.5 562 571.5 638.2
18 489 609.6 635 701.8
20 533.4 679.5 695.5 752.5
24 641.4 787.4 835.1 898.6

 

HOW TO ORDER A METAL JACKETED GASKET

The following information should be provided to the gasket supplier to order a jacket-gasket properly:

  • Outside diameter
  • Inside diameter
  • Shape per standard index
  • Type Number
  • Thickness
  • Materials (metal or metal filler)
  • Bar size
  • Radii
  • Distance from the centerline of the gasket to the centerline of bars