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American National Standard

Recommended Practice for Hardware Reinforcing
on Standard Steel Doors and Frames


ANSI/SDI A250.6-2003 (R2009)
Revision of ANSI/SDI A250.6-1997

  Foreword ANSI Information
  Table of Contents
1
General
  1.1 Purpose
1.2 Scope
1.3 Reinforcing methods
2
Metrication
3
Reference documents
4
Recommended reinforcing thickness
5
Recommended application of hardware
5.1 Mortised hardware
5.2 Field drilling and tapping
5.3 Thru-bolting
5.4 Sheet metal screws
6
Continuous hinges
Tables
1
Minimum hardware reinforcing thickness
2
#10/24 thread (nm)
3
#12-24 thread (nm)
4
Tap drills and clearance drills for machine screws with American National Thread form (nm)
Figures
1
Rigidity of angle or channel versus plate
2
Full #12-24 (nm) threads
3
Extrusion to create (3) full threads of #12-24 (nm)
4
Maintain a minimum of 65% of full thread
5
Full thread shall not fall below 65%
6
Sex bolted
7
Improper thru-bolting
Appendices
A
Conclusion
B
Bibliography

1 General

1.1 Purpose

It is the intention of this publication to furnish users and prospective users of standard steel doors and frames with practical information regarding accepted design methods for reinforcing and recommended practices for proper field preparation for builders’ hardware.

1.2 Scope

The information contained herein pertains to doors and frames manufactured in accordance with ANSI/SDI A250.8/SDI-100 “Recommended Specifications for Standard Steel Doors and Frames” published by the Steel Door Institute. It is not intended to reference architecturally specified or specialized situations beyond the scope of this document or documents herein.

1.3 Reinforcing methods

This standard recognizes as equal a variety of reinforcing methods produced by unique manufacturing processes. These processes include forming options (see figure 1) or integral gussets or fillets on lighter gauge members to achieve strength and performance equal to heavier gauge members.

1.3.1 Where reinforcements require tapping for machine screw threads, an equivalent number of threads may be rendered in a lighter gauge part with a pierced and dimpled (“extruded”) hole as compared to a heavier gauge part manufactured with conventional processes. For example, equal thread depth can be achieved on a piece of 0.067" (1.7 mm) metal and on a flat plate of 0.123" (3.1 mm) metal (see figures 2 and 3). The extrusion process results in equal strength, equivalent number of threads and a lighter weight than the parent metal or equivalent flat reinforcing plate.


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2 Metrication

Metric (SI Units) are indicated in parenthesis following conventional linear measurements. These are “soft conversion” approximates based on HMMA 803 “Steel Tables.” Units without metric equivalents are indicated as (nm) (e.g. screws).

3 Reference documents

  1. ANSI/SDI A250.8/SDI-100 “Recommended Specifications for Standard Steel Doors and Frames”
  2. ANSI/SDI A250.4 “Test Procedure and Acceptance Criteria for Physical Endurance for Steel Doors, Frames, Frame Anchors and Hardware Reinforcings”
  3. Machinery's Handbook

4 Recommended reinforcing thickness

The Manufacturer, based on individual construction methods and tooling capabilities, shall reinforce their product to insure performance in accordance with ANSI/SDI A250.4. This reinforcing shall include (unless noted otherwise) reinforcing and tapped mounting holes for template hinges and ANSI defined locks as specified. Additional reinforcing for surface applied hardware shall be built into the door at the factory when specified.

As a guide to specification writers, table 1 shows the minimum thickness of steel to be used for hardware reinforcing as endorsed by ANSI/SDI A250.8.

Table 1 – Minimum hardware reinforcing thickness

Hardware Item
Door
Frame
 
inches
mm
MSG No. (6)
inches
mm
MSG No. (6)
Mortise Hinge 1-3/8" [34.9 mm] Door (1)
0.093
2.3
12
0.093
2.3
12
Mortise Hinge 1-3/4" [44.5 mm] Door (1)(2)
0.123
3.1
10
0.123
3.1
10
Mortise Lock or Deadbolt (1)
0.067
1.7
14
0.067
1.7
14
Bored Lock or Deadbolt(1)
0.067
1.7
14
0.067
1.7
14
Flush Bolt Front (1)
0.067
1.7
14
0.067
1.7
14
Surface Bolt (3)
0.067
1.7
14
0.067
1.7
14
Surface Applied Closer (4)
0.067
1.7
14
0.067
1.7
14
Hold Open Arm (3)
0.067
1.7
14
0.067
1.7
14
Pull Plates and Bar (3)
0.053
1.3
16
0.053
1.3
16
Surface Exit Device (3)
0.067
1.7
14
0.067
1.7
14
Floor Checking Hinge
0.167
4.2
7
0.167
4.2
7
Pivot Hinge
0.167
4.2
7
0.167
4.2
7
Continuous Hinges (5)
Not Required
Not Required
Kick / Push Plate
Not Required
Not Required

NOTE: The minimum steel thickness for each specific gage is derived from the published figures of Underwriters Laboratories, Inc.

(1)Thinner steel may be employed as long as tapped holes used for mounting the hardware are extruded to produce an equivalent number of threads.
(2) If reinforcing is angular or channel shaped, 0.093" (2.3 mm) is permitted.
(3) When reinforcing is omitted, thru-bolting via the use of spacers or sex-bolts is required.
(4) Reinforcement shall occur on both sides.
(5) Refer to section 6.
(6) MSG No. to be used for reference purposes only.

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5 Recommended application of hardware

5.1 Mortised hardware

Standardized and ANSI defined preparations are made at the factory to allow installation of mortise hardware such as hinges and locks. Holes shall be made to precise diameters and accurately tapped to insure maximum thread engagement and holding strength. Cutouts shall be pierced to surround the mortised hardware item to close tolerances on three or all four sides. The hardware shall be installed using only the proper screws as furnished with or specifically recommended for each device.

NOTE: The installer must exercise caution upon initial insertion of screws to prevent cross threading, especially with the smaller diameter screws.

5.2 Field drilling and tapping

Doors and frames shall be prepared by the installer in the field for surface applied hardware, such as surface closers or holders, track type concealed closers or holders, pulls, exit device cases, or vertical rod latches. In addition, some hardware such as anchor hinges, thrust pivots, pivot reinforced hinges or floor mounted pivots must be field prepared due to design variations or to provide adjustment that can only be provided at time of installation. The installer shall use a template provided with the device or the device itself to locate hole spacing.

5.2.1 A suitably sized punch shall be used to locate the drilling for pilot holes to prevent drill creeping, off-center holes and improper screw alignment.

IMPORTANT NOTE: Use only the correct size drill for pilot holes, as recommended by “Machinery’s Handbook” (see table 4). Larger holes will decrease screw holding power causing the screw to be pulled from the reinforcing under normal stresses (see figures 4 and 5).

Tables 2 and 3 illustrate the effect of variances in pilot hole sizes on thread holding power.

Table 2 - #10-24 thread (nm)        
Drill Size
Drill Diameter
% Full Thread
       
#23
0.154''
66%
  Table 3 - #12-24 thread (nm)
#24
0.152''
70%
 
Drill Size
Drill Diameter
% Full Thread
#25
0.149''
75%
 
#15
0.180''
%66
#26
0.147''
79%
 
#16
0.177''
70%
#27
0.144''
85%
 
#17
0.173''
75%
"Machinery's Handbook" recommendation in BOLD   "Machinery's Handbook" recommendation in BOLD

Table 4 - Tap drills and clearance drills for machine screws with American National Thread form (nm)

Size of Screw
No. of
Threads
per
Inch
Tap Drills
Clearance Hole Drills
No.
or
Diam.
Decimal
Equiv.
Drill
Size
Decimal
Equiv.
Close Fit
Close Fit
Drill
Size
Decimal
Equiv.
Drill
Size
Decimal
Equiv.
0
.060
80
3/64
.0469
52
.0635
50
.0700
1
.073
64
72
53
53
.0595
.0595
48
.0760
46
.0810
2
.086
56
64
50
50
.0700
.0700
43
.0890
41
.0960
3
.099
48
56
47
45
.0785
.0820
37
.1040
35
.1100
4
.112
36*
40
48
44
43
42
.0860
.0890
.0935
32
.1160
30
.1285
5
.125
40
44
38
37
.1015
.1040
30
.1285
29
.1360
6
.138
32
40
36
33
.1065
.1130
27
.1440
25
.1495
8
.164
32
36
29
29
.1360
.1360
18
.1695
16
.1770
10
.190
24
32
25
21
.1495
.1590
9
.1960
7
.2010
12
.216
24
28
16
14
.1770
.1820
2
.2210
1
.2280
14
.242
20*
24*
10
7
.1935
.2010
D
.2460
F
.2570
1/4
.250
20
28
7
3
.2010
.2130
F
.2570
H
.2660
5/16
.3125
18
24
F
I
.2570
.2720
P
.3230
Q
.3320
3/8
.375
16
24
5/16
Q
.3125
.3320
W
.3860
X
.3970
7/16
.4375
14
20
U
25/64
.3680
.3906
29/64
.4531
15/32
4687
1/2
.500
13
20
27/64
29/64
.4219
.4531
33/64
.5156
17/32
.5312

.


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5.2.2 The installer shall assure that tapped holes have 75% of full thread (considered a normal condition). This percentage shall not fall below 65% to be considered adequate for proper hardware fastenings. Drills shall be positioned so the bit enters the reinforced area in perpendicular position as holes formed at angles will not permit proper seating of the screw head. After the proper pilot holes are drilled, proceed with the tapping operation. The tap shall match the thread size of the screws provided and the tap shall be held perpendicular to the surface.

5.3 Thru-bolting

Where reinforcing has not been specified or provided for other than mortised hardware, attachment shall be accomplished by thru-bolting. The hardware manufacturer’s instruction sheets shall be closely followed for recommended procedures. Where thru-bolting is required on hollow metal doors, spacers or sex-bolts shall be used to prevent collapsing of face sheets as illustrated in figures 6 and 7.


NOTE: The most popular thru-bolting applications are door closers, exit devices, overhead holders, pulls and bar sets.

5.4 Sheet metal screws

Sheet metal screws are normally used to attach accessory hardware such as kickplates, mail slots, room numbers, identification signs, and in many instances, push or pull plates. These areas are not reinforced beyond the thickness of the face sheets. Properly sized holes and correct sheet metal screws as provided with the hardware item or as specified in the mounting instructions shall be used for hardware attachment.

5.4.1 The best performance is achieved when the space between the threads is equal to or greater than the thickness of the face sheets.

6 Continuous hinges

6.1 Standard preparation for continuous gear type or barrel type hinges shall not include any factory reinforcing, drilling and/or tapping in doors or frames. All mounting shall be prepared in the field by the hardware installer.

6.2 For continuous hinges that require reinforcing (either for fasteners, door weight, door size or frequency of use situations) reinforcing shall be indicated at the time of order.

6.2.1 Standard reinforcing shall be a 0.067" (1.7 mm) steel strip no less than 1-1/4" (31.7 mm) in width securely welded inside the hinge edge of doors and hinge jamb door rabbet of frames.

6.2.2 Optional reinforcing shall be a 0.067" (1.7 mm) steel strip no less than 1-1/4" (31.7 mm) in width securely welded inside the hinge jamb door side face of frames.

6.3 The hardware installer shall carefully follow the hinge manufacturer’s instructions for fastener preparations.

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Appendices

Appendix A
(informative)
Conclusion

It has been the experience of the Steel Door Institute that most failures of hardware attachments have been caused by improper field installation rather than insufficient reinforcement. It is quite obvious that it is easier to tap an oversize pilot hole than to tap one of correct size necessary for maximum strength. Oversized holes will not ensure adequate product performance.

Manufacturing tolerances and dimensions may not always be consistent on machine and sheet metal screws when compared with different sources of supply.

The material used for the manufacture of screws is also a factor in the overall performance of the attachment. Stainless steel, for example, is a stronger fastener than aluminum or plain carbon steel. On installations where vibration or unusual frequency of operation is a factor, the use of thread locking inserts, liquids on threads, or binding heads should be considered.

Standard steel doors and top grade builders hardware are made to provide many years of service and are very compatible. The specification writer and construction superintendent must be aware, however, that proper installation methods must be considered on an equal basis with door and hardware construction requirements to achieve this compatibility on the job.

Appendix B
(informative)
Bibliography

  • HMMA 830 "Hardware Selection for Hollow Metal Doors and Frames"
  • HMMA 840 "Guide Specification for Installation and Storage of Hollow Metal Doors and Frames"
  • ANSI/SDI A250.7 “Nomenclature for Standard Steel Doors and Frames”
  • SDI-117 “Manufacturing Tolerances for Standard Steel Doors and Frames”
  • SDI-122 “Installation and Troubleshooting Guide for Standard Steel Doors and Frames”

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American National Standard

Approval of an American National Standard requires verification by ANSl that the requirements for due process, consensus, and other criteria for approval have been met by the standards developer.

Consensus is established when, in the judgement of the ANSl Board of Standards Review, substantial agreement has been reached by directly and materially affected interests. Substantial agreement means much more than a simple majority, but not necessarily unanimity. Consensus requires that all views and objections be considered, and that a concerted effort be made toward their resolution.

The use of American National Standards is completely voluntary; their existence does not in any respect preclude anyone, whether they have approved the standards or not, from manufacturing, marketing, purchasing, or using products, processes, or procedures not conforming to the standards.

The American National Standards Institute does not develop standards and will in no circumstances give any interpretation of any American National Standard. Moreover, no person shall have the right or authority to issue an interpretation of an American National Standard in the name of the American National Standards Institute. Requests for interpretations should be addressed to the secretariat or sponsor whose name appears on the title page of this standard.

CAUTION NOTICE: This American National Standard may be revised or withdrawn at any time. The procedures of the American National Standards Institute require that action be taken periodically to reaffirm, revise, or withdraw this standard. Purchasers of American National Standards may receive current information on all standards by calling or writing the American National Standards Institute. No part of this publication may be reproduced in any form, in an electronic retrieval system or otherwise, without prior written permission of the publisher.

Published by Steel Door Institute 30200 Detroit Road, Cleveland, Ohio 44145-1967 Copyright © 2003 by Steel Door Institute All rights reserved.

 

Foreword

(This Foreword is not part of American National Standard A250.6-2003)

The first edition of this standard was developed under the auspices of the Technical Committee of the Steel Door Institute and published in 1978 as SDI-107 “Hardware on Steel Doors (Reinforcement – Application).” In 1994, the word “standard” was added to the document’s title and the decision was made to promulgate SDI-107 as an American National Standard. A250.6 was officially approved by the American National Standards Institute on October 22, 1997. Substantive changes between SDI-107 and the revised and redesignated A250.6-1997 “Hardware on Standard Steel Doors (Reinforcement – Application)” include the addition of metric equivalents, revised tap and drill sizes to eliminate those that are not recommended, and a better definition for “factory mortise.”

In 2001, the TC-1 Committee of the Accredited Standards Committee A250 initiated the 5-year review process, and changed the title of A250.6 to “Recommended Practice for Hardware Reinforcing on Standard Steel Doors and Frames” to more accurately define the content of the standard. In addition, this revision includes the following substantive changes: Addition of Appendices A and B, both informative; discontinuation of the use of “gauge” in favor of decimal equivalents; addition of information relating to continuous hinges; redefinition of the scope to exclude “architecturally specified or specialized conditions.”

Suggestions for improvement gained in the use of this standard will be welcome, and should be sent to the Steel Door Institute, 30200 Detroit Road, Cleveland, Ohio 44145-1967.

The organizations of the Accredited Standards Committee A250 that have approved this standard are as follows:

  • American Institute of Architects
  • American Iron and Steel Institute
  • Builders Hardware Manufacturers’ Association
  • Canadian Steel Door Manufacturers’ Association
  • Door and Hardware Institute
  • Factory Mutual Research Corporation
  • General Services Administration
  • Hollow Metal Manufacturers’ Association / Division of National Association of Architectural Metal Manufacturers’ Association
  • Insulated Steel Door Institute
  • International Conference of Building Officials
  • Intertek Testing Services
  • Manufactured Housing Institute
  • National Association of Home Builders
  • Steel Door Institute
  • Underwriters Laboratories Inc.
  • Window and Door Manufacturers’ Association

The Accredited Standards Committee A250 TC-1 developed this standard had the following personnel at the time of approval:

Robert Berhinig, Chairman
J. Jeffery Wherry, Secretary

Organization Represented Name of Representative
American Institute of Architects Christopher Bushnell
American Iron & Steel Institute Robert Wills
Amweld Building Products, LLC Allan Ashachik
Benchmark Commercial Doors Randall Barber
Builders Hardware Manufacturers’ Association Mike Tierney
Canadian Steel Door Manufacturers’ Association Bud Bulley
Ceco Door Products Thomas R. Janicak
Curries Company Stan L. Horsfall
Deansteel Manufacturing Company Claus D. Heide
Door and Hardware Institute John Geniesse
Factory Mutual Research Corporation Mark Tyrol
General Services Administration Donald McGaha
Hollow Metal Manufacturers’ Association / Division of National Association of Architectural Metal Manufacturers Russell Tauscher
Ingersoll-Rand Kurt Roeper
International Conference of Building Officials Paul Armstrong
Insulated Steel Door Institute Steve Jasperson
Intertek Testing Services Nancy Kokesh
The Kewanee Corporation Jason Lisewski
Magnatrax Corporation Craig Ordmandy
Manufactured Housing Institute Mark Nunn
Mesker Door Company Stephen C. Frates
National Association of Home Builders Jeff Inks
Pioneer Industries Kamal Sheikh
Republic Builders Products Craig J. Ordmandy
Security Metal Products Corporation. Dan Buffenbarger
Steel Door Institute J. Jeffery Wherry
Underwriters Laboratories Inc Daniel Kaiser
Window & Door Manufacturers’ Association Rick Perry

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