Frequently Asked Questions

SDI has received many questions from design professionals over the years. The most common questions have been answered by industry experts and are categorized in the sections below.

What is the acceptable gap between leaves on a pair of exterior steel doors?

The clearance between the door and frame shall be a maximum of 1/8″ for both single swing and pairs of doors. Refer to section 2.1.8 in A250.8 for clearances for meeting edges and undercuts for non-rated and fire rated applications.

Since these are exterior doors, an open gap is not recommended and weather-stripping should be provided to seal the perimeter and meeting edge of the opening.

How do you recommend indicating the size of the leaves in the schedule? I typically specify the overall opening size, but if one leaf is bigger than the other I don’t know the correct way to specify it.

Your specification should be very precise if there are unusual dimensions. For example, if an opening is 5’6” wide and the active leaf is 3’0” then your specification should state the dimensions of both leaves since they are different sizes.

If the gap between the meeting edges of a pair of hollow metal doors is greater than 3/16” (1/8” plus the 1/16” tolerance), can the deficiency be overcome by applying a metal astragal? How about with fire rated doors?

For non-rated pairs of doors, there is no specific code requirement for a maximum meeting edge clearance. The end user or architect may approve clearances greater than 3/16”, but should consider the effect on security and appearance.

For rated openings, the 3/16” meeting edge clearance is measured from the “pull” or “wide” side of beveled doors. The 3/16” is the maximum clearance allowed per NFPA 80, regardless of the use of a flat bar astragal. Listed wrap-around metal edges may be an option and should be installed in accordance with the edge or door manufacturer’s listing.

The meeting edge clearance between double egress pairs of doors, measured from one side only, may potentially exceed 3/16” since the measurement would be from the “pull” side of one door to the “push” side of the other door. In this case, an allowance should be made for the degree of bevel.

Is the +/- 3/64” tolerance on door width determined from the nominal or net dimension of the door leaf?

The +/- 3/64” tolerance is applicable to the manufacturer’s net dimension. The net dimension may vary depending upon the manufacturers’ design, i.e. beveled hinge and lock edge, beveled lock edge, square hinge edge, or square hinge and lock edge. For a manufacturer with a beveled hinge and lock edge design, the math would look like this:

  • A door is ordered at a nominal width of 3’0”;
  • The net width of that door will be 35 13/16”
  • The + 3/64” tolerance means it can be 35 55/64” (widest)
  • The – 3/64” tolerance means it can be 35 49/64” (narrowest)

Even at the narrowest dimension, it would still be within the NFPA 80 tolerance of 1/8” on both sides—36.000 minus .125 (x 2) equals 35 3/4”. In SDI-117, figure E in section 5.1 the dimensions are based on the NET door width. In figure B of section 4.2 there are the dimensions and tolerances for the frame.

What are the benefits of choosing a steel door for exterior openings instead of aluminum?

Steel doors typically lend themselves to a wider selection of builders hardware than do aluminum doors. They also provide more diverse options for fire ratings.

What is the preferred protective coating for grouted frames?

A quality bituminous coating should be applied to the throat of the frame.

What is the difference between face welding and a full profile weld?

Face welding is weld applied only to the face of the frame, usually at the 45 degree joint. The full profile weld is applied to the full contour of the frame at the intersection of the head and the jambs. Since most manufacturers can fire rate their frames knocked down (in 3 pieces), welding is not required and is usually for cosmetic appearance and ease of installation. Since the frame throat is sheltered by a wall on all sides, full profile welding is usually not required.

Is it better to specify galvanized or galvannealed steel?

Galvannealed. Galvanized steel has that spangled look and is often found in weights of G40 and G60. You don’t want to specify it for your steel doors and frames because primer doesn’t adhere very well to it. Specify galvannealed steel at A40 or A60 instead because it offers excellent paint adhesion. In fact, when you specify to ANSI/SDI A250.8 then that’s exactly what you get.

You don't recommend grouting of frames, but acknowledge grouting is used for sound suppression. Is there another material that is recommended?

Materials like fiberglass batt, mineral wool, strips of drywall, and acoustic coatings (e.g. Silent Running) may be added to the throat of the frame to improve acoustic performance. Performance may not equal that of a grouted frame.

What qualifies a door as being Maximum Duty? Core and welding construction?

Maximum Duty doors are listed as Level 4 in accordance with ANSI A250.8 and Physical Performance Level A in accordance with ANSI A250.4. The door core, hardware reinforcement, face gauge, and edge construction are design attributes that contribute to the door assembly performance rating.

With the advent of equivalent gauge studs, does the reduced metal thickness affect pressure fit anchors?

Reduced metal thickness may contribute to local buckling of the stud depending on the door weight and location of the performance enhancing features in the wall stud. Flange stiffening grooves and web embossments will resist local buckling if properly located.

Stud manufacturers are adding ribs and texture to provide equal deflection criteria, but are thinner on the web portion of the stud that the anchor is pressing against. Is this thin section dimpling/bending when the weight of the door swings and puts pressure on the anchors?

Transfer of door loads to wall studs may cause local buckling of the wall stud if the stud gauge is too light. Additional jamb anchors will spread the load more evenly on the wall stud.

Does the door core selection have any effect on mitigating weld "dimpling"?

Yes, doors specified with vertically steel stiffened cores are prone to some level of surface imperfection due to the internal stiffeners being welded to the face sheets. Doors intended for more aesthetic applications should avoid vertically steel stiffened cores in lieu of a laminated polystyrene, honeycomb or polyurethane core.

How can "dimpling" caused by welding be avoided?

The most common method to minimize aesthetic imperfections is the utilization of projection welding versus spot welding. Both are forms of resistance welding, but projection welding utilizes a formed projection on one piece to localized the weld current and minimize the resulting imperfection. While this technique will minimize the imperfections, all welding tends to leave some degree of surface imperfection. More information can be found in the Aesthetics section of A250.8 Appendix B.

Is there likelihood of "dimpling" on the faces of a steel reinforced door?

Yes, whenever metals are welded there is significant heat involved, potentially resulting in surface imperfections. Most steel doors have the majority of the welding done on the hinge and lock edges in order to minimize imperfections on the faces.

What is the industry standard on exterior steel doors and water resistance?

SDI 127H contains information on water penetration. In summary, door assemblies are not manufactured to be watertight. Seals and thresholds are required to ensure water resistance of the opening assembly in normal environmental conditions.

In situations where water penetration is a concern, the contractor must seal all joints that are exposed to the elements after the frame assembly is installed. Whenever possible, it is strongly recommended that glass and glazing be installed on the exterior rabbet of the frame assembly.

What is the industry standard for weeps at the bottom of an exterior door with vertical stiffeners and mineral fiber insulation?

There is not an industry standard on weep holes. They are not required and not all manufactures incorporate such a configuration in their doors. If a manufacturer should determine that some sort of drain needs to be part of the door construction, how they accomplish that is up to them—whether by designing it into the door or by drilling holes/slots after manufacturing. A sealed flush cap on the top of the door should be requested if the opening is expected to be located in an area where moisture is expected (e.g. – exterior opening). Some holes in the bottom of the door are used by manufacturers to suspend the doors during coating operations.

Where is the recommended location of the electric hinge?

A hollow metal door manufacturer can locate the prep for an electric hinge at most any location a customer would desire. As the load bearing capacity of the reinforcement is reduced to accommodate the additional holes for the wiring, the middle location on a 3 hinge door would be recommended. The third hinge down on a 4 hinge door would be the recommended location. These locations also closely match the level of the strike.

Are steel doors always ordered with the latch prepared on the center of the edge?

All hollow metal doors are manufactured as two pans with an edge seam. Some are made with an offset concealed edge seam, which is 1/4″ from the push side of the door. This is suitable for the commonly specified mortise locks and mortise exit devices that have 1-1/4″ faceplates, and are automatically centered when abutted to the 1/4″ edge seam. (1/4″ + 1-1/4″ + 1/4″ = 1-3/4″).

How do I select the right type of steel for steel doors and frames?

The three most common steel types are cold rolled steel, galvanneal steel, and galvanized steel.

  • Cold rolled steel, suitable for most interior applications, is uncoated steel with a factory applied coat of primer.
  • Galvannealed steel is carbon steel coated with an iron-zinc alloy. It provides excellent corrosion protection when combined with a coating of quality prime paint and is adequate for most interior and exterior applications. SDI recommends use of the A Series, both A40 and A60, for primer adhesion. A60 is superior to A40 for inhibiting rust. SDI does not recommend the G series because of inferior primer adhesion properties.
  • Galvanized steel is carbon steel treated with a full zinc alloy. It provides superior rust protection but has poor adhesion properties for prime or finish paint.
What are the different door cores available from most manufacturers, and how do I select the best type for my application?

Steel doors are differentiated by their core, with each type having a different set of properties and performance characteristics. The five most common cores are honeycomb, polystyrene, polyurethane, steel stiffened, and temperature rise.

  • A honeycomb core door is used for interior and exterior openings where high thermal insulation is not required.
  • Polystyrene core doors are the most commonly specified insulated core and are suitable for applications requiring an R or U factor (a measure of insulating performance).
  • Polyurethane core doors provide superior insulating properties and are suitable for exterior openings in cold climates.
  • Steel stiffened core doors feature steel ribs in the interior of the door and are ideal for high traffic, non-aesthetic applications.
  • Temperature rise core doors are used when a fire resistance rating is required to retard the transfer of heat from one area to another (a stairwell, for instance).
What are the rough opening dimensions for a hollow metal frame?

The rough opening dimensions for a standard hollow metal frame are as follows:

  • Assumes std. 2″ face, butted wall.
  • “A” = opening width + 4 1/2″
  • “B” = opening height + 2 1/4″

So for a 3’0” x 7’0” door & frame, the rough opening would be 40 1/2″ x 86 1/4″

Can you give me a quick explanation about R and U values?

R and U values relate to insulation performance characteristics. The higher the R value, and the lower the U value, the higher the insulating properties of the product. Polystyrene and polyurethane cores have higher insulating properties than honeycomb and steel-stiffened core doors. 1 ¾” thick commercial steel doors will have R values that range from approximately 1.5 to 3.

Why has the thermal resistance of hollow metal doors changed recently?

The R and U values have been updated as a result of a change to the ASTM testing methods of SDI 113 (Standard Practice for Determining the Steady State Thermal Transmittance of Steel Door and Frame Assemblies). In the previous test method only a portion of the door was tested, which does not reflect operable conditions of the door, frame and hardware. The new version of the standard tests the entire assembly, which represents real-world conditions. Architects should only use the numbers from the new thermal performance standard method.

I'm an architect. What does the change to the testing method of thermal performance mean to me?

The testing method was updated to enable architects and other design professionals to specify openings using real-world thermal performance data. Knowing the thermal conductivity of a door opening (U-value), allows you to specify according to the desired energy efficiency of a building or any applicable code requirements for the efficiency of the building envelope.

I have a steel door specification with interior door core construction type A, D or F and exterior door core construction type B, C, E or F. Can you tell me what these door cores are?

The references cited are from an outdated SDI 100 specification. The new specification, SDI 100 ANSI A250.8, does not contain letter designations for core material. The updated document provides a performance-based standard, such that an architect can be assured the doors will perform to the performance levels outlined in SDI 100 A250.8, regardless of core material. If an architect specifies a particular core material they will be limiting the number of manufacturers that supply that product, and perhaps the variety and styles of doors available to them. That is why it is better to base your choice on performance characteristics.

I am considering specifying seamless-edge doors and trying to decide which design I should specify: vertical seam edge filled, dressed smooth, intermittently welded seams, edge filled and dressed smooth, or continuously welded seam, dressed smooth? How do the three options differ?

Seamless edge doors are specified primarily for aesthetic considerations. Edge-filled and dressed smooth doors are treated with a filler material and subsequently sanded smooth and painted. Intermittently welded seam doors, are welded at intervals along the seam, treated with a filler material and subsequently sanded smooth and painted. Continuously welded seam doors provide an uninterrupted weld the entire height of the door edge with no added filler material and subsequently sanded smooth and painted.

Can fire-rated doors be repaired in the field?

Contact the manufacturer of the fire-rated door and/or frame prior to performing the repair.

Are closer covers required for annual fire door inspection?

This varies by manufacturer, but typically the closer cover is for cosmetic purposes only and is not required in order to maintain the listing of the product. One exception could be if the label indicating a listing for use on fire doors is attached to the cover rather than to the closer body or arm. In this case, losing the cover would result in a product without the required label.

Why do not all fire doors require gasketing?

This varies depending on which code has been adopted, but using the 2015 IBC as an example, gasketing is required when the requirements for a fire door assembly include the limitation of air/smoke infiltration when tested to UL 1784. If a section does not reference UL 1784, gasketing is not typically required. In the 2015 IBC, Section 716.5.3.1 – Smoke and Draft Control, falls under section 716.5.3 which addresses door assemblies in corridors and smoke barriers. Fire doors in these locations would require gasketing. Sections 716.5.4 Door Assemblies in Other Fire Partitions and 716.5.5 Doors in Interior Exit Stairways and Ramps and Exit Passageways do not reference UL 1784 and would not be required to have gasketing according to the 2015 edition.

Can you expand on where exactly gasketing is required?

Typically, gasketing at the head, jambs, and meeting stiles is needed for doors that are required to limit air infiltration to a specified level when tested in accordance with UL 1784. For some locations, usually related to elevators, a bottom seal is also required. In the 2015 edition of the International Building Code, references to UL 1784 can be found in section 710.5.2.2, section 716.5.3.1, and in several sections within Chapter 30. Although these code sections do not specifically mandate gasketing, the gasketing is required in order to limit the air infiltration to the level specified in the code.

Do the door gaskets need to have a smoke/fire-rating?

Typically, all products used as a part of a fire door assembly are required to be listed, including gasketing (80-2016: 6.4.8). Thresholds are required by NFPA 80 to be noncombustible or listed (80-2016: 6.4.9). Listed gasketing materials are also available for doors that are required to limit air/smoke infiltration when tested in accordance with UL 1784. Indications of suitability for use on fire- and/or smoke-door assemblies is indicated in the gasketing manufacturers’ catalogs.hout astragal) that is free swinging in both directions. To my understanding, only a single swing door (single or double) can be considered for fire-rating. And that a double door needs the services of an astragal.

Does the discharge exterior stairs door need to be rated?

Most exterior stair discharge doors are not required to be fire rated, but there are some circumstances where exterior walls are required to be rated and for those locations, fire door assemblies would be required.

Your fire-rated course notes that a firepin is typically required in a LBR application. When is a firepin not required on a fire-rated door LBR assembly?

The ability to omit the fusible fire pin on a LBR assembly depends on the listing of the hardware as well since Listed fire exit hardware and flush or automatic bolts often require the use of the pin to maintain the fire-rating of the door assembly. For steel doors, the pin and its use is a function of the hardware listing much more often than the doors on their own.

We have a client that needs a fire-rated double door (without astragal) that is free swinging in both directions. To my understanding, only a single swing door (single or double) can be considered for fire-rating. And that a double door needs the services of an astragal. Can a fire-rated floor closer be used for such a requirement? If so, can the doors still be considered as fire-rated doors?

Fire-rated doors may be listed for single swing, standard pairs (both leaves swinging in same direction), or double egress pairs (one leaf swings one direction, and the other leaf swings the opposite direction). The manufacturer’s listing will state if an astragal is required, as not all doors require the use of one.

However, we are not aware of any fire listing on a pair of doors that is free swinging in both directions–with or without astragal.

Is it possible to have a 3-hour fire-rated door with a plastic laminate or FRP skin?

We are not aware of any 3-hour fire-rated FRP doors. Any type of laminate that is attached to a fire door must be done so in accordance with the manufacturer’s labeling procedures.

Can we keep the existing doorframe and replace the door and transom with a steel door and steel transom? Can the transom be 1-hour rated?

The door, frame and transom must all be compatible and rated by the testing agency.

Simply installing a rated door into an existing frame may not allow for the rating to be maintained. If the frame, door or transom is modified and the manufacturer’s installation requirements are not followed the rating is not valid.

Is there an exception or modification to the rule of using deadbolts in addition to latches on fire entry doors to single dwelling units?

We are not aware of any exception or modification to this rule. You may wish to check with the AHJ in your area. You are correctly quoting the provisions contained in SDI 118, which is taken from the requirements contained in NFPA 80.

15.5 Section 714.2.3 (2000 IBC) requires fire doors to be tested for smoke and draft-control in accordance with UL 1784 with an artificial bottom seal. Is an artificial bottom seal required as part of the final installation of a fire door?

No. The artificial bottom seal is a component of the UL 1784 testing protocol and is not a requirement of the final door installation.

The UL 1784 test standard states, “In order to obtain information on the extent of air leakage at the ungasketed bottom gap of a test sample, an artificial seal may be applied to the bottom 6 inches (152.4 mm) of the test sample. The artificial seal may be any material, such as an impermeable sheet or tape.” By testing air infiltration with the artificial bottom seal in place, any air that would have passed through the bottom 6 inches of the door opening is not considered, so leakage at the balance of the perimeter can be accurately measured.

What are the basic hardware requirements for fire door assemblies?

They must have a minimum number of approved hinges, a listed and labeled self-latching device and a labeled self or automatic-closing device.

Do I need to use intumescent sealants for fire-rated steel doors?

Generally speaking, no, but the requirement is a function of the individual manufacturer’s listing. Intumescent products are typically used for a smoke and fire barrier on wood doors and are activated by heat. Given the basic properties of steel (e.g. it expands when exposed to heat), sealants are typically not required on steel doors.

Instead of using the provided anchors, am I allowed to substitute to different anchors that I prefer working with when installing fire rated frames?

Anchors may be substituted provide they are like-for-like anchor types and are approved to be used in fire rated applications.

Am I required to use fire rated caulk between the frame and wall on fire-rated openings?

Reference the manufacturer’s installation instructions because it depends upon how the frame was tested and approved. Generally speaking, fire rated caulk is not required unless specified in the manufacturer’s installation instructions.

Both SDI 118 and ANSI A250.8 mention that "Doors with glass lights, or doors equipped with fire exit devices may not have louvers unless permitted by local building codes". Do you know the reasoning behind why louvers cannot be used on doors with fire exit hardware?

That requirement has been part of SDI 118 and A250.8 because they reflect the information in NFPA 80 and 101.

Traditionally, louvers were not intended for use in doors that serve as a means of egress out of a building, and exit devices are typically only used on egress openings. This may have been due to the smoke issue and the passage of smoke/heat through the louvers that could prevent people leaving. We have heard that the NEC or some form will allow exit hardware on doors so it could be up to local approval.

I’m renovating a 30 year old building that has similar doors and frames throughout the interior. Some have fire labels, and others don’t. What should I do to ensure fire code compliance?

Start by contacting the certification agency noted on the remaining fire labels, such as Warnock Hersey (Intertek) or UL, to see if they can trace the assemblies of the non-labeled products. The agency can then provide field labeling services if needed.

If none of the doors or frames have a fire label (or the labels have been painted over and are not legible), try finding any identifying marks on the doors and/or frames themselves. Occasionally there will be a paper sticker or stamp across the top or bottom of a door which may be useful in tracing the assembly back to a manufacturer or supplier. Some steel door manufacturers may incorporate an embossed logo on the hinge reinforcement of the door, which may be visible by removing a hinge blade.

Steel frames may have an embossed logo or certification mark on the rabbet or face. If this information is found, I would suggest taking it to Intertek and/or UL to see if they can trace it back to the listed designs. A quick search on either online Certification Directory might help as well.

I’m renovating an older building and only the frames have fire labels. Is that okay?

NFPA 80 and Chapter 7 of the IBC both require the door and frame to be labeled. There may be some unique instances where the door and frame assembly only has one label (Category D – Door/Frame Assembly), but that is uncommon and not accepted by all states.

Most builders hardware is required to be labeled per NFPA 80. The hardware may bear a physical label or in some cases the certification mark could be embossed or on the packaging (typical for gasketing). There are some exceptions to this, particularly for hinges as noted in Section 4.2.6 of NFPA 80 (2019) which states, “Specification of items of a generic nature, such as hinges, that are not labeled shall comply with the specifications contained in this standard,” and for protection plates as noted in Section of NFPA 80 (2019) which states, “Labeling shall not be required where the top of the protection plate is not more than 16 in. above the bottom of the door.”

If installing an accessory onto the top portion of a fire door, does the accessory need a fire label or listing if only penetrating one side of the door? what if penetrating completely thru the door? Would this change the field installation or rating of the accessory?

Components used as part of a fire door assembly are required to be listed for that purpose, unless there is an exception in NFPA 80. One example of an exception is that a listing is not required for protection plates installed within the bottom 16 inches of the door. Generally, NFPA 80 doesn’t distinguish between where the item is located or whether it is attached on one side of the door or through the door.

Why are annual inspections required by "qualified" persons, not "certified" persons?

NFPA 80 does not define the term “certified person,” but “qualified person” is defined as: “A person who, by possession of a recognized degree, certificate, professional standing, or skill, and who, by knowledge, training, and experience, has demonstrated the ability to deal with the subject matter, the work, or the project” (80-2016: 3.3.96). Chapter 5 states that acceptance testing shall be performed by a qualified person (80-2016: NFPA 80-2016 does include the term “certified” in a new section on field labeling, which requires field labeling to be performed only by individuals or companies that have been certified or listed, or by indivuals or companies representing a labeling service that meets certain criteria (80-2016: 5.1.4). This section applies to field labeling of a component, but a certification is not required for an inspection.

Is there a label or listing required when installing power door operators and accessories onto a fire rated doors?

The intent of NFPA 80 is to require each component installed on a fire door assembly to be listed or labeled, unless it is specifically excluded from this requirement. Although NFPA 80 does not specifically address labels for power door operators and accessories, the standard does require door closers to be labeled (80-2016: 3.3.38). In addition, NFPA 80 requires power operated fire doors to have a releasing device that automatically disconnects the operator at the time of a fire, allowing the door to close and latch (80-2016:

Are smoke rated doors required to have a rating label?

“Smoke rated” doors are typically required by two different types of wall construction:

Smoke Partitions – where doors are required by the code, they must be tested per UL 1784. The code states that when these doors comply only with UL 1784, they “shall be permitted to show the letter “S” on the manufacturer’s labeling.”

Smoke Barriers – most smoke barrier walls are required to have a 1 hour fire-resistance rating and therefore the doors are also required to be fire rated. The codes states that the doors shall be tested to UL 1784 and shall show the letter “S” on the fire-rating label of the door.

Is it permissible to paint over the fire label on a hollow metal door or frame?

You may paint over an embossed label on a door or frame, unless prohibited by the specification. However, it is never permissible to paint over a Mylar label or applied metal label for a door or frame. The reason is that once a label is painted over it is impossible to discern the label information.

Can we use European Standard Fire Rated Ironmongery on UL-labeled fire rated hollow metal doors?

Probably not. There are numerous differences between the EN (European) test standard and UL 10C, the North American standard. A major difference is that EN test standards do not require a hose stream test.

The Authority Having Jurisdiction determines if a combination of products allows for the opening to maintain a fire rating. Generally speaking, any listed fire rated product must be matched with similarly rated and approved products. If the doors have been tested with the hardware then most likely the rating will be extended to the opening.

However, if the door must be modified—cut out for the hardware, or any other modification—then it is likely that the door would not maintain its fire rating. The general rule is that no modification can be made to a fire door without approval of the rating agency, such as UL or WH.

Can doors with louvers be positive pressured fire labeled?

Doors with UL listed louvers may be positive pressure fire rated up to 90 minutes. The louver must be located in the bottom half of the door with a maximum size of 24″ x 24″.

Are frames required to have a label?

Fire rated frames must have either an attached label or an embossment in the metal of the frame. The attached labels may be made of metal or tamper-evident Mylar design.

How is authority to field label conferred on a company and from whom does this authority come?

NFPA 80, “Fire Doors and Other Opening Protectives” contains provisions specific to the case of field modifications of fire door assemblies and the subsequent field labeling of the assembly. In part, NFPA 80 states;

“The laboratory with which the product or component being modified is listed shall be contacted through the manufacturer and a written or graphic description of the modifications shall be presented to that laboratory. Field modifications shall be permitted without a field visit from the laboratory upon written authorization from that laboratory.”

So the authority for field labeling is conferred by the third-party listing agency with whom the product is listed, and is communicated in writing.

If hardware is labeled, does it mean it can go on any labeled door?

Labeled hardware is permitted to be used on any brand of fire door, provided that door is properly listed and labeled for that hardware application. For instance, a door listed and labeled for single-point locks cannot be fitted with panic or fire exit hardware. A door specifically listed and labeled for this hardware application must be used.

Can doors with louvers be positive pressure fire labeled?

Yes. Fusible link louvers with a maximum size of 24″ x 24″ can obtain up to 90 minute fire labels.

Can the frame be cut or modified in any other way in the field without voiding the label?

Yes, NFPA 80 Chapter 4 specifies the allowable modifications for the application of hardware. No other modifications are allowed.


SDI 127-G – Environmental Considerations Relating to Factory Painted Steel Doors and Frames

Sustainability Information

LEED Credit Information

SDI has an online AIA/GBCI course called Sustainability & Steel: Benefits & Certifications for Building with Recycled Materials with detailed information on the green elements of steel. It provides one AIA HSW and/or GBCI hour.

How do you handle the 500 mile minimum on regional restrictions?

USGBC LEED, Materials & Resources, Section 5.1 and 5.2 provide the guidelines for the 500 mile minimum requirement. The guidelines expand beyond the location of the manufacturer to include where the materials were extracted and processed. Most architects agree that this is the most difficult credit to achieve due to the nature of the global economy.

What's so great about recycling steel? Forests are renewable, trees grow back and waste wood is shredded and recycled as compost or chips.

Steel is an infinitely reusable material without any loss of function, durability or quality. At the end of their useful life, about 88% of all steel products and nearly 100% of structural steel beams and plates used in construction are recycled into new steel products.

Isn't wood more energy-efficient than steel?

On the contrary, steel doors can be up to four times more energy efficient than wood doors. Steel doors and frames allow minimal air infiltration which results in less energy loss between the door’s interior and exterior surfaces. Steel is dimensionally stable and when properly designed, can provide an exceptionally tight building envelope for less air loss and better HVAC efficiency over time.

What about steel doors with a polystyrene or a polyurethane core? They're not recyclable, are they?

Yes. All steel doors-honeycomb core, polystyrene core, polyurethane core and steel-stiffened core – are recyclable.

What LEED points are available for using steel, including steel doors and frames?

The U.S. Green Building Council Leadership in Energy & Environmental Design (LEED) Green Building Rating System aims to improve occupant well-being, environmental performance and economic returns of buildings using established and innovative practices, standards and technologies.

Steel construction materials, including hollow metal doors and frames, typically generate credits in green building certification programs and reduce the building’s carbon footprint.

Materials & Resources Credit 4: Recycled Content intends to increase demand for building products that incorporate recycled content materials, thereby reducing impacts resulting from extraction and processing of virgin materials. Steel building products contribute positively toward points under Credits 4.1 and 4.2:

Credit 4.1 (1 point) “Use materials with recycled content such that the sum of post-consumer recycled content plus one-half of the pre-consumer content constitutes at least 10% (based on cost) of the total value of the materials in the project.”

Credit 4.2 (1 point) “Use materials with recycled content such that the sum of post-consumer recycled content plus one-half of the pre-consumer content constitutes at least 20% of the total value of the materials in the project.

Does the Steel Door Institute recommend grouting frames?

We believe there are more risks than rewards when grouting frames. After all, a properly anchored frame without grout can pass fire and hose stream, cycle, and even impact tests.

Grouting should never be specified for drywall construction. It is water-based, and when drying, the moisture only has a few places to go. The first is into the drywall, which weakens it and may hinder the frame’s integrity or ability to retain anchors. The other places the moisture could go are into the hardware or the bottom of the frame. And we all know what happens when metal is in a moist environment—rust.

Grout is usually not necessary for masonry construction either. However, when done properly, grout can improve durability of the frame and sound deadening. This may be desirable for specific openings, such as an external door assembly in masonry where forced entry may be an issue.

There is also a misconception that grout is required for fire rated frames, which is not true.

If you do decide to grout frames, it is essential that:

  • It is only used in masonry openings, never drywall.
  • It is hand troweled and not pumped. The excess water from pumpable slurry cases rust.
  • It does not contain anti-freeze agents unless the frame is backcoated for corrosion protection.
  • The frame is braced during grout application to prevent bowing and sagging.

Failure to adhere to any one of these may result in frames that are rusted or out of square.

Instead of grouting strike bucket area in drywall, what should be used instead to prevent frame spreading attacks?

Most manufacturers can provide a Z-shaped anchor located just above the strike in the strike jamb.

Is it better to reuse existing frames or install new ones when retrofitting?

It depends on a variety of factors such as the condition of the wall, reinforcements, and frame. You will also want to verify the gauges of the door and frame are compatible, and also that the hinge and strike locations match.

It is best to inquire with the door supplier for fire rated openings.

Do you have standards on how to properly install hollow metal frames that I can reference in my specifications?

Yes, ANSI A250.11 provides recommended erection instructions for steel frames. Please reference SDI-122 to troubleshoot an issue with a frame that has already been installed

Does the distributor fabricate frames?

There are a small number of contract hardware and hollow metal distributors that have the capability to manufacture frames.

The distributor welds the frames in most cases. Many of them can modify doors and cut in glass light units as well. Distributors are often involved in fire labeling programs too, allowing them to label the door and frame.

What is the final step when installing hollow metal frames?

The final step in installing any frame is to double check for plumb and square before installing the door. Refer to SDI-122 for details.

Architects using hollow metal door and window frames on exterior openings sometimes incorrectly assume that frames are watertight. In fact, most seams in hollow metal frame construction are not welded nor sealed, unless by the painter. Many specifiers now write their specifications to include some of the following:

  • Full continuous TIG welds on all hollow metal frame joints, including both horizontal and vertical mullions. (Note: Not every shop is capable of TIG welds.)
  • Mullion construction with both joints of the two-piece mullion turned to the interior.
  • Continuous nailing flashing flanges on all framed construction with plaster to allow integral watertight flashing of the building paper to the nailing flange.
Can I use grout for drywall construction?

No. Grouting should never be specified for drywall construction. When grout is drying, the moisture only has two places to go. The first is into the drywall, which weakens it. This could hinder the frame’s integrity or ability to retain anchors. The other place the moisture could go is into the hardware or the bottom of the frame, which may result in rust.

Will an anchored frame be sturdier if it's grouted?

Grouting will not make a properly anchored frame any sturdier. In fact, drywall slip-on frames have passed fire and hose stream tests, cycle tests, and even impact tests with only anchoring.

What are the benefits and setbacks of grouting a frame in masonry construction?

If grouting is done properly it will not cause any issues with the frame. It will actually improve the sound deadening qualities. Unfortunately, thin pumpable slurry is often used and the excess water in it causes rust. Grout should always be hand troweled, never pumped.

For fire rated openings, you should verify with the frame manufacturer that if a bituminous coating is used to protect the steel frame against any corrosive effects of the grout its use will not negate the fire protection rating.

Does the requirement for a maximum gap of 1/8", plus or minus 1/16", apply only to the meeting edges of door pairs? What is the gap requirement for maximum gap between door and frame/stop at the hinge jamb and head? And strike jamb on single doors?

If a metal door has a gap between the meeting edges of a door pair that is greater than 3/16″ (1/8″ plus the 1/16″ tolerance), can the deficiency be overcome by applying a metal astragal?

If the gap at the bottom of a metal door is more than 3/4″, can the deficiency be overcome by adding an automatic door bottom or a metal astragal-like strip to the bottom edge of the door?

Refer to ANSI 250.8 paragraph 2.1.8 entitled “Design Clearance” and the subparagraphs underneath that. Those paragraphs specifically and clearly delineate and define the design clearances for between the door and the frame, between the meeting edges of pairs of doors, and the clearance measure from the bottom of the door to the bottom of the frame.

What is the industry standard for clearance around a steel door in a steel frame?

Where the doors are fire rated, these clearances are regulated by NFPA 80, “Fire Doors & Other Opening Protectives”. The clearance between the door and frame shall be a maximum of 1/8″. The clearance between the meeting edges of pair of doors shall be 3/16″. The clearance from the bottom of the door to the bottom of the frame should be a maximum of 3/4″. The clearance between the face of the door and the stop shall be 1/16″. See SDI 100 A250.8-2.1.8 for complete specifications.

While the clearances of non-fire rated openings are not regulated by the Building or Fire Code, they typically will follow the same values as a rated door.

Specialty Doors

SDI 128 – Guidelines for Acoustical Performance of Standard Steel Doors and Frames
Our free AIA course on Specifying Specialty Steel Doors provides detailed information on acoustic, blast, bullet, tornado, and more. It provides 1 AIA HSW CE hour and/or 1 GBCI CE hour.


What are the reasons for not over-specifying the STC rating?

Typically, doors with higher STC ratings have increased cost, weight and lead time.

Are STC rated doors provided with a label, similar to fire rated doors?

STC rated doors are generally supplied with a label that is either Mylar or metal, but the products are not listed like fire doors by agencies such as Underwriters Laboratories or Warnock Hersey. Labels are for manufacturer and rating identification purposes only.

What is the maximum rating tested for STC so far?

STC ratings would be specific to each manufacturer and design, typical higher range ratings are between 50 and 55.

What is the difference between STC and decibels?

TC is a single number rating that indicates the sound transmission loss over a defined range of frequencies of a door assembly between adjacent closed rooms. Higher values equate to better sound reduction performance.

Decibels dB, are used to express the intensity of a sound wave. Examples of decibels levels are:

  • 100-120 Deafening industrial machinery, jet engines
  • 80-100 Very loud cocktail party, boom box
  • 60-80 Quiet speech
  • 20-40 Faint soft whisper, recording studio
  • 0-20 Very faint acoustical laboratories, deep caves
Is it a requirement that STC metal frames be filled with grout or a sound retarding material?

Most manufacturers conduct acoustic tests with grout filled frames to optimize the lab performance. Acoustic performance will be reduced on frames over STC 40 when grout or sound retarding material is eliminated.

What is STC?

STC stands for “Sound Transmission Class”, a measure of the extent to which sound is prevented from being transferred from one area to another. The higher the STC value, the less sound transferred from one area to another.

The STC scale is a logarithmic progression, meaning that a jump of 3 points in an STC rating equates to a doubling in a door’s ability to prevent sound transmission. Acoustical doors are tested as an assembly comprised of the door, frame, hinges, and sound sealing system. See SDI 128 for more information.

The following chart illustrates the sound retardant performance associated with a range of STC values.

STC Value Rating Description
50-60 Excellent Loud sounds heard faintly or not at all
40-50 Very Good Loud speech heard faintly, but not understood
35-40 Good Loud speech heard but hardly intelligible
30-35 Fair Loud speech understood fairly well
25-30 Poor Normal speech understood easily and distinctly
20-25 Very Poor Loud speech audible
I have a specification that references an OITC value, is this the same as STC?

OITC stands for Outdoor-Indoor Transmission Class and is a measure of the ability of a building material or product’s ability to retard sound transmission. It is similar to STC, but it is not the same. As the name indicates, OITC is a measure of sound transmission from the external environment into the building envelope. Testing to establish an OITC value utilizes ASTM E-1332 Standard Classification for the Determination of Outdoor–Indoor Transmission Class. This standard uses a range of frequencies lower than the STC testing, to more closely replicate the sounds of rail and vehicular traffic.

Do you recommend a specific type of core for acoustical doors?

No, we recommend that the door selection be made on the basis of the STC value that has been specified. Multiple door core types may be capable of achieving the specified value, and can be documented by Certificates available from the manufacturer.

What level STC door do you suggest for an office building near an airport?

There are many variables that would determine the proper STC value, including the physical proximity of the office building to the airport. To ensure that the specification is properly developed, an acoustic consultant should be engauged to determine the Outdoor / Indoor Transmission Class (OITC) values.

I saw an image of a tornado resistant door with a vertical, top and bottom rods, but the bottom rod is no longer acceptable per ADA. Do tornado resistant doors have to have bottom rods?

Openings, specifically hardware, have been tested to comply with FEMA 320 and 361 that have the bottom bolt engaging into the hardware rabbet of the frame. This eliminates the bottom rod engaging into the floor and can be single acting function that would comply with ADA requirements.

Do SDI members offer products that meet FEMA 361 “Design and Construction Guidance for Community Safe Rooms”? What is approved?

Yes, SDI members offer door assemblies certified to FEMA 361. These openings must be tested and installed as a system including the hinge, door, frame, anchors and latching hardware. The architect or specifier should investigate the doors available that would satisfy the requirements for those openings.

We are building a safe room and the only tornado doors I find have a solid metal appearance. Are there tornado doors that are more aesthetically pleasing?

Some manufacturers have options for aesthetic finishes on these doors, but due to the severity of the testing requirements, almost all tornado shelter doors are very heavy-duty steel designs.

How do hurricane resistance ratings work? Are they pass/fail or are their levels like with fire ratings?

Hurricane resistance ratings are expressed in pounds-per-square-foot (PSF) values, and unlike fire ratings, there are no standard increments. In addition to the PSF values, they are either listed with or without “missile” impact ratings. In this instance, a missile refers to a 2 x 4 piece of lumber weighing 9 lbs. that is fired at the door at 35 miles-per-hour. A door assembly must withstand 3 impacts in order to have a missile impact listing. A typical door listing would be expressed as;

  • Design Pressure Rating +75/-65 PSF
  • Large Missile Impact – Yes

This listing indicates that the door assembly is rated for 75 PSF when loaded against the stops of the frame, and 65 PSF when loaded away from the stops of the frame.

Where are higher hurricane design pressures and missile impact ratings required?

As a general rule, the closer a building is located to the coastline, the higher wind speeds it is expected to experience. The wind speed and debris impact zones for Florida are defined by a map that is found within the Florida Building Code.

Can oversized hollow metal doors meet Miami Dade or Florida Building Code requirements or do they need to be standard sized doors?

Many SDI manufacturers have single swing doors that are 4’0” x 8’0″, and pairs that are 8’0″ x 8’0″, listed with the Florida Building Commission. Special sizes are also permitted by the code to be analyzed by a Registered Design Professional if they fall outside of existing approvals.

I have a specification that references ICC 500 and FEMA 361. Are these the same?

No, they are not the same, but they are both related to the construction of tornado shelters. FEMA 361“Design and Construction Guidance for Community Safe Rooms” is a guidance document, but FEMA does not regulate building construction. ICC 500 “Standard for the Design and Construction of Storm Shelters” is written by the International Code Council® and is referenced in the International Building Code in all Editions since 2009.

Can STC and blast resistant doors be fire rated? If so, can they be rated up to 3 hours?

The ability to fire rate STC and blast doors would be specific to each manufacture and it is recommended that you contact a quality manufacturer for their specific listing. Follow this link to a listing of SDI manufacturers to ensure you are supplied a top quality door.

What criteria should I look at when specifying a blast door?

To properly specify the desired blast resistance for a door assembly, the following information needs to be provided:

  • Peak blast pressure — such as 5 psi.
  • Either the blast duration (e.g., 60 milliseconds) or blast impulse (e.g., 150 psi-msec).
  • Direction of blast pressure loading (i.e., either seated or unseated).
  • Acceptable level of post blast event damage: typically limited to Response Categories I, II or III. In general terms, these ratings correspond to (I) no permanent damage, (II) permanent damage but the door remains operable, and (III) more severe damage with the door being inoperable after the blast.
Can blast resistant doors have veneers?

There is nothing in the standards that prohibit veneers, but they would have to be documented within the manufacturer’s certification to ensure that they pose no hazard to the building’s occupants.

Can blast resistant doors have glasslights?

Yes, the primary focus of the Department of Defense’s Unified Facilities Criteria is to protect against injury from architectural glazing, so many SDI member companies have certifications for doors with glasslights.

I have a specification that references “UFC 4-010-01 Minimum Antiterrorism Standards for Buildings”. What type of doors are required to meet this spec?

The Department of Defense created the referenced document to provide a minimum level of protection from blast forces from acts of terrorism. The door assemblies offered by SDI members are specifically engineered and certified for these applications, with a wide variety of blast resistant capabilities. In order to supply the correct door assemblies, you will need to know the PSI/MSEC value (pounds per square inch / millisecond). This is a value that has been calculated by a blast consultant, and would be expressed as a numerical value, i.e. 50 PSI/MSEC. The higher the value the more blast force the opening is designed to withstand. Matching that value to a manufacturer’s certification will allow you to select the correct door, frame, glazing and hardware configuration.

Note: There are many other blast resistant specifications in addition to UFC 4-010-01. Please also keep in mind that the version of the specification is critical, particularly with the UFC 4-010-01 specification.

Bullet Resistant

Are forced entry doors always bullet resistant?
No. These doors can have individual or combined characteristics of forced entry and bullet resistance.
Our client is requesting "bulletproof" doors, not "bullet resistant". Is there a certain bullet resistant level that qualifies as being “bulletproof” or are they simply using the wrong terminology?

They are using the wrong terminology, which is not uncommon. While the most common standard for bullet resistance, UL 752 Standard for Bullet-Resisting Equipment, has multiple levels of resistance, none are considered “bullet-proof”.

The table below lists the ratings for bullet resistance.

Rating Ammunition Weight (Grains) Min fps Max fps Number of shots
Level 1 9mm Full Copper Jacket with Lead Core 124 1175 1293 3
Level 2 .357 Magnum Jacketed Lead Soft Point< 158 1250 1375 3
Level 3 .44 Magnum Lead Semi-Wadcutter Gas Checked 240 1350 1485 3
Level 4 .30 Caliber Rifle Lead Core Soft Point (.30-06 Caliber) 180 2540 2794 1
Level 5 7.62mm Rifle Lead Core Full Metal Copper Jacket Military Ball (.308 Caliber) 150 2750 3025 1
Level 6 9mm Full Metal Copper Jacket with Lead Core 124 1400 1540 5
Level 7 5.56mm Rifle Full Metal Copper Jacket with Lead Core (.223 Caliber) 55 3080 3383 5
Level 8 7.62mm Rifle Lead Core Full Metal Copper Jacket Military Ball (.308 Caliber) 150 2750 3025 5
Level 9 .30-06 Caliber Rifle, Steel Core, Lead Point Filler, FMJ (APM2) 166 2715 2987 1
Level 10 .50 Caliber Rifle, Lead Core FMCJ Military Ball (M2) 709.5 2810 3091 1
Shotgun 12-Gauge Rifle Lead Slug 1.0oz 1585 1744 3
Shotgun 12-Gauge 00 Buckshot (12 pellets) 1.5oz 1200 1320 3
Are you aware of any manufacturers that provide bullet resistant doors that are also fire rated?

SDI Certified manufacturers of fire rated bullet resistant doors include Ceco Door, Curries, Deansteel, and Republic.

Other Questions on Specialty Products

Are there steel doors rated and designed for psychiatric hospitals?

There are not specific doors that are designed for psychiatric hospitals. Doors are built based on life safety, ADA and building code requirements.

However, specific hardware such as anti-ligature hardware, can be used for patient room doors to prevent tampering or use as an anchor point. The door hinges should be continuous or use sloped hospital tip hinges to prevent the patient from using the barrel as an anchor point. View panels in patient room doors that allow staff to check on a patient without entering the room should use laminated glazing.

Behavioral health facilities are subject to heavy use and possibly extensive abuse. Doors make up a significant percentage of the exposed wall surface in corridors and have a strong visual impact on these spaces. Painted steel doors are durable and can be easily touched up or refinished.

Specialty products, such as lead-lined and oversized doors, are heavier than typical doors. Is there industry guidance for constructing wall openings in steel stud framing that address the larger than typical forces acting on these heavier doors?

Guidance for design of steel stud walls for heavier doors can be obtained through members of the Steel Framing Industry Association or Steel Stud Manufacturers Association. Consider using additional jamb anchors to spread the load more evenly on the wall stud.

We have a distributor that does a lot of government work. They have alerted us to a specification for "forced entry resistant components" as regarding hollow metal door and frame openings. Can you direct me to any information that SDI might have on this subject or any other information source?

See our Forced Entry Resistant Doors and Frames page for information on specifying these products and a list of SDI Certified manufacturers.

We’re getting a lot of questions about improving security in schools. What types of doors can we use to enhance security?

Properly functioning steel doors around the perimeter of a school building are one of the least expensive solutions for guarding against unauthorized entry. Routine maintenance is recommended to verify the doors are self-closing, and latch every time they are closed. If the doors are in a state of disrepair that prevents them from properly closing and latching, they should be replaced.

Do SDI members provide lead-lined doors for radiation shielding applications?

These SDI member companies offer doors and frames with radiation shielding options. They are primarily used in medical facilities where the containment of radiation from X-Ray operations are a primary concern.


How should I store steel doors and frames onsite?

All frames shall be stored under cover. Assembled frames shall be stored vertically. The units shall be placed on at least 4″ (102 mm) high wood sills or in a manner that will prevent rust or damage, even if they are galvanized or primed. The use of non-vented plastic or canvas shelters that can create a humidity chamber shall be avoided.

Are knock down frames standard for all door openings?

The type of frame is up to the specifier’s discretion. To answer the question directly, knock down (K-D) frames are not standard for all openings, as many are specified as welded frames.

What is the definition to A, B, C, D, E and F cores?

Per SDI-100-1991 the cores were listed as follows:

  • A – Kraft Honeycomb
  • B – Polyurethane
  • C – Polystyrene
  • D – Unitized Steel Grid
  • E – Mineral Fiberboard
  • F – Vertical Steel Stiffeners

These are now archaic references and should be treated as such.

Our firm designs healthcare facilities, and uses AIA MasterSpec as a basis for our specifications. In the Steel Door Frame section, it calls for a "bituminous coating; cold applied asphalt mastic SSPC-Paint 12 compound for 15 mil thickness per coat." We have a subcontractor questioning the need for the bituminous coating. I seem to recall that the coating is primarily required at exterior door frames where moisture getting in behind the frame may be a problem. Can you shed any light on the reason for bituminous coating?

Some Architectural Specifications require steel frames to be back-coated with a “bituminous” product for corrosion protection and sound control. The term “bituminous” is defined as an asphalt or tar material obtained as a residue from heat refined petroleum. For years it was not recommended by the Steel Door Institute for frames to be factory back-coated due to issues with packaging, shipping and handling. This procedure was more effectively accomplished at the jobsite by the contractor or appropriate trade immediately prior to installation of the frame.

Modern materials now offer manufacturers the opportunity to back-coat frames with a more user and environmentally friendly product. Some of these coating s are VOC (Volatile Organic Compounds) free and do not present the handling issues common to bituminous products. Today, multiple SDI manufacturers offer the option of factory back-coated frames which utilize these newer materials.

In Appendix B of SDI-100, "G" type galvanizing is not recommended. Is it correct to infer that the "A" Types are recommended? I understand that A60 is the thickest option. In a marine climate, would you say painted A60 is our best bet?

SDI recommends type A, both A40 and A60, over type G due to the superior primer adhesion qualities. A60 is superior to A40 for rust inhibiting.

SDI Technical Data Series 100 has been republished as an ANSI Standard, A250.8. In addition, please see our Technical Data Series 112 “Zinc-Coated Standard Steel Doors and Frames.” The difference in the A and G designations are explained. Table 1 of that document gives coding designations for A40, A60, G60 and G40.

What modifications am I eligible to make to the opening protective?

Modifications are only eligible when referenced and described in both the third-party certification and the manufacturer’s published instructions.