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OP — Oval Pipe

How to Specify

Using tables from the National Fuel Gas Code or our Sizing & Application Guide, determine the diameter of venting required. The Sizing & Application Guide also offers tips on good design including multi-appliance system sizing and design.

How to Purchase

Vent FAQs

OP — Oval Pipe


OP Oval Pipe

  • Offers all the advantages of round pipe, and may be used for the following types of installation.

4" Oval:

  • Conventional Type B
  • Type B-2x4 when used with firestop
  • Type BW-2x4 with recessed heater

5" Oval:

  • Type B
  • Type B-2x4

HC_OP_TBGV line art pipe section ovalType B

Sizes 4" and 5" may be installed with 1' minimum clearance to combustibles.

Type BW

Four-inch oval vent (when installed in 2x4 stud wall with recessed heater) requires clearances as determined by use of 4OBPWS hold-down plate, 4OCP ceiling plate spacers, and 4OFS firestop spacers.

Type B 2x4

Four and five inch oval vent (when installed in 2 x 4 stud wall, not using a recessed heater) requires clearance as determined by use of 4OFS or 5OFS firestop spacers at each ceiling level.

Available Oval Pipe Lengths (inches)

4" oval pipe
5" oval pipe--

Oval Pipe dimensions (inches)

ModelSizeDim. ADim. B
4OP__*4"7 1/162 7/8
5OP__*5"10 3/42 7/8

* Add length to complete Model Number.