D+AS MAGAZINE

TECHNICAL TIPS — Garage Doors and Rolling Doors

© 2004 Door & Access Systems
Publish Date: Summer 2004
Author: LeRoy Krupke
Page 68

Garage Doors and Rolling Doors
Similarities and Differences

By LeRoy Krupke, P.E.
Director of Advanced Technology, Overhead Door Corporation

Garage doors and rolling doors are both "vehicular access doors." However, these two doors differ in several notable areas such as wind load, fire compliance, automatic operation, thermal characteristics, and durability.

These differences can affect the overall performance of the door system. Knowing these differences can improve your ability to sell the right product to your customers.

Here’s a brief overview of some of the key similarities and differences.

Wind Load

Similarity: The same wind load principles apply to both garage doors and rolling doors.

Difference: Garage doors are designed to withstand wind pressure when installed with a reinforcement member across the backside of each door panel. The load from the wind is simply transmitted into the doorjamb through the rollers and track.

Rolling doors are designed much differently. There is no reinforcement across the backside of a rolling door. The door withstands wind pressure by locking itself into the door guides, which are attached to the doorjambs.

The jamb loads created from this locking effect are greatly magnified on rolling doors. The curtain wind-lock forces pull the doorjambs together. It is very important that the building owner is made aware of these higher loads during the design of doorjambs. (See DASMA TDS-251, available on the DASMA Web site.)

Fire Compliance

Similarity: When using foam plastic insulation, both garage doors and rolling doors must comply with the applicable code requirements.

Difference: Rolling steel doors can be installed as fire doors in fire-rated walls, where they are required to have a fire rating in accordance with the applicable building code. Garage doors cannot be installed in fire-rated walls as defined by the building codes.

Automatic Operation

Similarity: Automatic operation of both garage doors and rolling doors is governed by requirements in UL 325. Labeling and listing of the operators for both doors will include terms of conformance to UL 325.

Difference: Safety requirements for automatic operation of garage doors are dependent on end use, i.e. commercial versus residential. Federal law requires new residential opener installations on and after January 1, 1993, to comply with UL 325. However, this federal law does not cover such requirements for commercial operator installations on rolling doors and commercial garage doors.

Thermal Properties

Similarity: Both garage doors and rolling doors are tested to the same standards for air infiltration and thermal resistance (R-value). Thermal transmittance (U-factor) is also commonly used. U is the inverse of R, i.e., U = 1/R.

Difference: The curtain thickness of rolling doors is typically much thinner than garage doors. This results in smaller R-values, indicating less of an insulation barrier. Rolling doors will also have higher air infiltration values. There are many more joints in a rolling door as compared to garage door section joints. Each slat interface allows a small amount air to infiltrate the building.

Durability

Similarity: A garage door or a rolling door may each be suitable for certain applications. Both will close the same opening sizes. Under the same duty cycle, they will have a similar expected life.

Difference: Rolling doors are capable of withstanding a more severe duty cycle. Rolling doors can withstand minor impacts from fork trucks and shipping containers without significant damage.

When you are aware of the similarities and differences between each product, you can help a builder, contractor, or owner make an informed choice as to the right product to purchase and install. You are encouraged to contact any garage door or rolling door manufacturer for further help.

LeRoy Krupke has been an active member of both the Commercial & Residential Garage Door Technical Committee and the Rolling Door Technical Committee since the inception of DASMA in 1996, and has held various positions within DASMA.