View Ports / Peep Doors / Sight Ports

Need Peep Doors or Sight Ports? Contact FIS for Specs, Lead Times, and Quotes.

Learn More About Furnace Improvements Services (FIS)

Patented technology • Measurable ROI • Trusted by top refineries

Our Services

  • Fired Heater Revamp

  • Boiler Revamp

  • New Heater and Boiler Design

  • In-person and Virtual Training

  • Decarbonization Solutions

  • Engineering Studies

  • Trouble Shooting

Our Scope

  • Process Engineering

  • Mechanical Engineering

  • Structural Engineering

  • 3D Modeling

  • CFD Modeling

  • Project Management


500+

Heater Studies completed

29

Years in Business

15

Countries Served

4

Patented Technologies

2

Global Offices

By The Numbers:

Overview

  1. Peep doors (also called view ports, sight ports, or observation ports) are provided in the radiant section of the heater to allow viewing of burner flames, tubes, tube supports, and refractory.

  2. Critical areas of observation include burner flames and pilots, the hottest portion of tubes.

  3. Peep doors should be accessible either from the Grade or from platforms.

  4. We have an extensive list of references for our Peep Doors — a selection is publicly available here

    Download our brochure

Glass Peep Door

  • Consists of a front high-temperature glass pane, a handle and a flap.

  • Pull down the handle to lift the flap behind the glass pane.

  • The operator can look into the firebox through the glass pane.

  • The glass pane is heat and breakage-resistant.

Side-Hinged Peep Door

  • Consists of a spring handle, side-hinged door, and locking lever.

  • The door contains ceramic fiber packing with a SS Liner.

  • The locking lever ensures tight closing of the door.

  • The operator has to unhook the locking lever and open the door

Top-Hinged Peep Door

  • Consists of a spring handle and a top-hinged door.

  • The hinged door contains ceramic fiber packing with a SS liner.

  • Lift the spring handle upwards to open the door.

Peep Door Blocks

  • Peep door blocks are made from a special vacuum manufacturing process. These offer the best strength and rigidity.

  • Peep door blocks are mainly made from Folded blanket module.

FIS offers a wide range of customizable peep door solutions to suit your unique application needs. We work closely with our customers to deliver precision-engineered doors tailored to their exact specifications.

Customizations include:

  • Peep door size and arrangement

  • Material of construction

  • Accessories and add-ons

  • Placement and orientation of components

  • Design modifications to existing parts

  • Supply of entirely new peep door designs as per customer specifications

Other Peep Door Configurations

Wire Mesh Glass Peep Door (17 1/2” X 6 1/2”)

Single Hinge Glass Peep Door (7” X 11”)

Double Hinge Glass Peep Door (7” X 11”)

Top Hinged Peep Door (5” X 9”)

Side Hinge Peep Door (11 5/8” X 15 9/16”)

Side Hinge Peep Door (9” X 24”)

Need Peep Doors or Sight Ports? Contact FIS for Specs, Lead Times, and Quotes.