Recommendations for Measuring Door Gap Dimensions

1 Speed, accuracy, and above all consistency are es-sential when determining the clearance Dimensions around and under swinging fire doors are within NFPA 80 s specifications. Tape measures and rulers are not efficient or practical tools for Measuring door gap Dimensions . The best method for Measuring door gap Dimensions is to use a tool of the appropriate thickness that can be inserted between the door frame and door, the door and the floor, and between opposing vertical edges (aka, meeting stiles) of paired doors.

2 Remember, you are confirming door gap dimen-sions are within NFPA 80 s specifications not mea-suring them, per se. In addition to using a tool to measure door gaps consistently, you need to follow the same pattern of checking the gaps every time. Resist the temptation to esti-mate door gap sizes by sight or only spot-checking them at certain points along the edges. NFPA 80 s clearance Dimensions apply to the entire perimeter around and under the doors, and between paired doors. In other words, the door gap Dimensions must be within NFPA 80 s specifications along the full height of the vertical edges and across the full width of the doors at the tops and bottoms.

3 (See Fig. 2.)Knowing where to check clearance gaps is im-portant to assessing the doors correctly. NFPA 80 re-quires gaps to be measured on the pull-side of doors. Specifically, gaps are measured at the outermost leading edge of the doors and the rabbets of the door frames. (See Fig. 3 and Fig. 4.)Many doors have beveled ver-tical edges that create additional operating clearance between door frames and doors. Beveled vertical edges allow doors to have less clear-ance at the outermost edges and open and close without rubbing against door frames.

4 When measur-ing door gaps, only the position of the outermost lead-ing edge of the doors in relation to the door rabbet of the frames (or the opposing door edges of pairs) is following steps can be applied to any door-gap-tool or material of the appropriate thickness:Step 1, Identify the Door Frame and Door Construction. Using the door gap dimen-sions listed in Table 1: Clearance Dimensions for Swinging Fire Doors, select a tool with a thickness equal to the maximum or minimum clearance dimen-sion for the type of door you are evaluating ( , 3/16-in.)

5 Max. and 1/16-in. min. for hollow metal door frames and hollow metal doors). Step 2, Insert Door Gap Tool Between Door Frame and Door. Standing on the pull-side of the door, in-sert the tool into the gap between the door frame and door; in the following order:(a) Latch edge top to bottom, then(b) Hinge edge top to bottom, then(c) Top edge left to right. Using a firm grasp, slide the tool all the way along the door edge. Pay close attention to how the tool fits into and slides along the gap. When the gap dimension is at its maximum size, the tool should substantially fill the gap (snuggly, not loosely); no lateral movement should be gap Dimensions must be with-in NFPA 80 s specifications along the full height of the vertical edges and across the full width of the doors at the top and are measured at the outermost leading of the doors and the rabbets of the door 1 The DoorGap Gauge Copyright 2018 Door Safety, LLC.

6 All rights reserved. No reproduction without express written permission is forMeasuring Door Gap Dimensionsof Swinging Fire Doors with Builders HardwareBy Keith E. Pardoe180417 Where the tool fits into gaps, check for lateral movement by twisting the tool side-to-side. Any lateral movement no matter how small indicates the gap dimension is larger than allowed by NFPA 80, and it should be cited as a deficiency on inspection reports. For example, the maximum door gap dimension for 3/4-hour (and greater) rated wood fire doors is 1/8-in.

7 No over-tolerance dimension is permitted. When a 1 tool fits into the gap, with no lateral movement, the gap is within NFPA 80 s specifications. However, when the 1 tool has any amount of lateral move-ment, the gap is larger than 1/8-in.; it doesn t matter how much larger. In the case of fire-rated wood doors (and doors other than hollow metal), the maximum clearance is allowed to be any dimension up to and including 1/8-in. Less than 1/8-in. clearance is acceptable, but it cannot be greater than 1/8-in. Consider this, an additional 1/32-in.

8 Of clearance in this case is twenty-five (25) percent greater than the 1/8-in. maximum dimension that s significantly larger. More importantly, it is the difference between compliance and non-compliance with NFPA 80 s the gap dimension is smaller than the max-imum or minimum dimension allowed, the tool will not fit into the gap. In the case of minimum gap dimen-sions, when the tool cannot fit into the gap the clear-ance dimension is too small and should be cited as a deficiency. Fig. 4 Measuring Door Gap at Vertical Edge of DoorFig.

9 3 Measuring Door Gap at Top Edge of DoorFig. 2 Measuring Door Gaps Around and Under DoorsThe measurement is taken be-tween the bottom outermost edge of the doors and the top of the floor surface beneath the 3, Insert Door Gap Tool Under Bottom of Door. Regardless of the door frame and door con-struction, and the level of fire rating of swinging doors, NFPA 80 limits the maximum clearance dimension between the bottom edges the doors and the floor surface to 3/4-in. (see Fig. 5) no over-tolerance di-mension is permitted.

10 Where bottoms of swinging doors are more than 38 inches above the floor, the maximum clearance di-mension is reduced to 3/8-in. (See Fig. 6.)The measurement is taken between the bottom outermost edge of the doors and the top of the floor surface beneath the doors. (See Fig. 5 and Fig. 7.) Door sweeps and shoes (and other types of gasketing products) attached to the bottoms of doors are not included in this measure-ment they are not tested or listed for extending the length of fire-rated doors. Likewise, the height of thresholds under doors is not included in this measurement.