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WOCDs Explained

What classifies as a window opening control device and how they fit into building codes

The term Window Opening Control Device (WOCD) is widely recognized in the fenestration industry. But at times, there’s still confusion about what hardware meets the requirements to be classified as a WOCD.

WOCDs are one type of fall prevention device, which are intended to help reduce the risk of accidental falls from windows and are tested, installed and labeled to comply with the ASTM F2090 Standard. Not all fall prevention devices, however, are considered WOCDs. For example, window guards are fall prevention devices, but aren’t considered as WOCDs. 

The 2006 editions of the International Code Council (ICC) I-codes introduced a requirement to provide window fall protection for operable windows where the lowest portion of the window opening is located greater than 72 inches above the exterior finished grade or surface below. Window fall protection is to be provided by one of the following:

A minimum dimension from the finished floor to the lowest portion of the window opening of:

  • V    24 inches for buildings governed by the International Residential Code (IRC), or 
  • V    36 inches for dwelling units within Group R-2 or R-3 buildings as governed by the International Building Code (IBC). (Note: the IBC originally had a 24-inch sill height but moved to a 36-inch height starting with the 2012 IBC.)
  • Limit the sash opening to a less than a 4-inch dimension such as a vent limiter. Note that this option would not be allowed on an operable window that is required for emergency escape and rescue.
  • Installation of a window fall prevention device that complies with the ASTM F2090 standard (WOCD, a specialized window screen or a window guard.)
  • Under the IBC only, in Group R-2 and R-3 occupancies, applications where the lowest portion of the window opening is more than 75 feet from the exterior finished grade or surface below, installation of an ASTM F2006 (Specification for Window Fall Prevention Devices for Non-emergency Escape (Egress) and Rescue (Ingress) Windows compliant device (specialized screen or window guard).

So, what exactly constitutes a WOCD? ASTM F2090 provides guidance.

Guidance per ASTM F2090-2021

WOCDs were first introduced officially as fall prevention devices in the 2008 version of ASTM F2090, Standard Specification for Window Fall Prevention Devices with Emergency Escape (Egress) Release Mechanisms. To meet ASTM F2090 requirements, a WOCD must:

  1. Limit the sash opening to less than 4 inches dimension, and
  2. Be able to be disengaged by either:
      - installation of two independent single-action devices (for example, a lever that can be flipped, with two such devices installed on the same window), or 
      - one dual-action device that requires two separate, distinct and consecutive actions to release the WOCD, such as holding a button in while sliding a lever, and
  3. Upon release of the WOCD, the sash must be able to be fully opened as may be needed for emergency escape or rescue. The WOCD device must then automatically reset when the sash is re-closed such that the device will again limit the sash opening to a less than 4-inch opening. 

One of the key points of clarification in the latest version, ASTM F2090-2021, is that partial compliance to this standard is not permitted. To claim compliance to this standard, all of the applicable requirements must be met.

When properly designed, tested, specified and installed, appropriately configured WOCDs can help reduce the potential for falls from operable windows of various styles while allowing full opening of windows designated for emergency escape or rescue. WOCDs may be factory-installed, applied as a field kit or applied as an after-market device.

In addition to the ASTM F2090 standard, other efforts to help better define, explain and specify the proper use of WOCDs continue.

Code revisions

The IBC, International Existing Building Code (IEBC) and IRC building codes have included provisions for window fall prevention since 2006. Now, FGIA and the Window and Door Manufacturers Association (WDMA) have jointly filed a proposed code change that, while not affecting current physical requirements, would clarify IEBC sections 505.2 and 702.4 to require that replacement windows incorporate WOCDs in installations otherwise covered by the IBC.

The Group B proposal by FGIA and WDMA is expected to be heard during ICC Committee Action Hearings March 27-April 6 in Rochester, New York. If the committee approves it, the proposal will next be heard in Public Comment Hearings Sept. 14-21 in Louisville, Kentucky. If the proposal prevails there, it advances to ICC’s Online Governmental Consensus Vote for approval before it would be incorporated into future code language in the next cycle.

Joint FGIA/WDMA Technical Bulletin

A new Technical Bulletin, Clarification of the Definition of a Window Opening Control Device (WOCD), created by FGIA to be jointly published with the WDMA, explains what qualifies as a WOCD and what distinguishes them from the other similar-looking hardware like night latches, vent stops or vent limiters, which are not governed by the ASTM F2090 or other standards and should not be used on windows designated for emergency escape and rescue.

ASTM F2090-21 is complete. Proposed code revisions are in progress for the next IEBC revision, and the new joint FGIA/WDMA Technical Bulletin will soon be available through FGIA’s Online Store and through WDMA. The industry’s work to promote a better understanding of WOCDs and their proper use is ongoing. 


Kathy Krafka Harkema FGIA

Kathy Krafka Harkema

Kathy Krafka Harkema is the Fenestration and Glazing Industry Alliance's U.S. Technical Operations Director.