Dock Seals

Dock Seal Design

Working with your loading bay system Dock Seals & Dock Shelters provide environmental protection and a guide for trucks docking with your facility. By compressing between the trailer and wall, dock seals effectively guard against high wind, outside rain, snow, heat, cold, birds, mice & other pests. To achieve all these benefits differences in door widths, dock heights, and bumper projections must be taken into consideration.

Key Dock Dimensions

1. Dock Height
2. Door Width
3. Door Height
4. Dock Bumper Projection
5. Slope

Getting the right seal for your application is our mission, to do that the above dimensions are an essential component.

• Dock Seal Brochure
• Dock Dimension Submittal (PDF)

Dock Seal Depth

Ideally all dock seals should extend 5" past the face of the dock bumper. This ensures that there is adequate compression while also limiting over compression. To achieve this it is critical we first determine the distance from where the dock seal mounts out to the dock bumper face.

A) Dock Seal Depth
B) Lintel + Dock Bumper Depth
C) Lintel Depth
D) Dock Bumper Depth
E) Dock Seal Projection Past Bumper Face

Dock seal Depth is also affected by any slope over 2%. To accommodate the trailer angle, dock seal pads will be wedged to match the trailers angle when docked. This is a critical step that may require different Dock Bumpers as well. Our goal should always be to keep trailers a minimum of 4" from the wall. If your bumpers are not sufficient there is a risk trailers will impact on the wood backer of the dock seal.

Sealing Your Dock Door Width

There are three common door widths in the loading dock industry, 8', 9', and 10' wide. In contrast, common trailers range from 8' to 8'6" wide. Taking into consideration trailers will rarely dock perfectly the ideal opening size is 7'6". You'll note Loading Dock Supply offers three dock seal patterns C Series, ZN, and ZT Series to seal the widths designed to achieve this 7'6" opening; for Full access see our Dock Shelters.

C Series - 8' Wide Doors
Designed for use on the most common door width of 8', the C Series uses a vertical pad is wedged 9" at the back to a 12" face. This pad is also available in a 15" face for doors measuring 8'6" wide.

ZN Series - 9' Wide Doors
The less common 9' wide dock door calls for our specialized ZN option. Wedged from a 7.5" back to a 16" wide face the ZN Dock Seal has a thicker inside lip than the C series, measuring in at 4" thick. This ensures the seal is rigid enough to remain effectiveness for the life of the Dock Seal.

ZT Series - 10' Wide Doors
10' wide dock doors are a rare occurrence which require an extra large dock seal face. Measuring in at 7.5" at the back and 21" at the face the ZT Dock Seal follows suit with the ZN models, showcasing a thicker inside lip for lasting performance.

All three dock seal models come standard with a high visibility yellow guide stripe set 3" in from the inside edge to indicate the 8' center. This helps trucks line up with your dock door in addition to your dock bumpers. The ZN and ZT models carry an additional feature of an large wear shield patch sewn into the bottom corner to reduce wear and tear.

Sealing Your Dock Door Height

Loading dock door openings range from 8' to 10' in height or even greater. Adding in the common dock height of 48", this puts the top of doors in a range of 12' to 14'. In contrast, the standard Height range for 53' LTL dry van trailers is 12' to 13'6". To seal this range there are three standard header set ups.

18" High Dock Seal Header (Top)
When the top of the dock door finishes at 12', the general rule of thumb is to defer to a 18" high header. This ensures the standard range of trailers seals tightly to keep out rain, dust, and pests. If you are looking to keep costs down, ask our sales team about alternatives to 18" high headers.

12" High Dock Seal Header (Middle)
For dock doors finishing between 12' and 13'6" high, a 12" high head pad with drop curtain is standard. ideally the top of the 12" head pad will finish at or above 13'6", while the drop curtain sewn to the bottom of the face will hang to seal the remaining space below.

Curtain Header (Bottom)
For docks finishing at 14' or higher a curtain header is the ideal choice, as a foam header will never be impacted at this height. Designed to hang 18" to 24", the curtain style header contains a pocket enclosed steel pipe for placement and a pocketed foam pipe at the base of the drop to improve compression and rigidity. Curtain headers are an easy option for any door height, simply increase the dock seal vertical height to finish at 14' to use this option on doors finishing lower than 14'.