Robert I. Merrill Co.
Complete Door Opening Specialists
80 Years of Business in Salt Lake City, Utah
Member of the Door & Hardware InstituteFeaturing Architectural Hardware Consultants
Frequently Asked Questions


What are the ADA (American Disabilities Act) Door and Hardware Code Requirements?

Often a Facility Manager is placed in a situation where he has to face trade-off decisions when it comes to meeting codes.  The first thing to do is to determine what are the most critical factors facing the installation of doors and hardware.  Every facility is expected to meet the requirements of life safety codes and the ADA requirements.  But some facilities have additional requirements to take into consideration and meet.  These can include additional life safety issues, high loss prevention requirements, higher need to protect the occupants of the building and liability and insurance costs. 

See official ADA Information

see also:


Some General Guidelines:

Clear Opening Width (4.13.5):

  • 32" minimum measured with door open
  • 90 degrees face of door to stop on strike jamb
  • Projection of hardware is not taken into account
  • At least one leaf of a pair must comply
  • Shallow closets (less than 24") are exempt

 Thresholds (4.13.8):

  • 1/2" high maximum (3/4" for exterior sliding doors)
  • Slope no greater than 1:12

 Door Hardware (4.13.9):

  • Shape of operating devices must be easy to grasp with one hand
  • No tight grasping, tight pinching, or twisting of the wrist to operate
  • Levers and u-shaped handles are acceptable
  • No specific projection is required for pulls
  • No higher than 48" above finished floor

 Closing Speed (4.13.10):

  • Sweep period - 3 seconds Minimum
  • From an open position of 70" to a point 3 inches from the latch
  • Measured to the leading edge of the door
  • Delayed action is not a code requirement

 Opening Force (4.13.11):

  • Exterior hinged doors: (Reserved)
  • Interior hinged doors: 5 lbf. Maximum
  • Sliding or folding doors: 5 lbf. Maximum
  • Fire doors: up to the authority having jurisdiction (size 3 recommended for fire doors per NFPA80)

 Automatic Operators (4.13.12):

  • If automatic operators are used, shall be low energy type complying with ANSI/BHMA A156.19
  • 3 seconds minimum to open to backcheck
  • No more than 15 lbf to stop door movement
  • Automatic operators can solve code problems
  • Clear opening width on pairs
  • Door opening force
  • Maneuvering clearances
  • Small vestibules

What are the ADA Washroom or Bathroom Code Requirements?


Accessible bathrooms for each gender must be clearly marked with an International Symbol of Accessibility sign. This sign is to be mounted 60 inches above the floor to the centerline of the sign. In addition, it must have raised characters, including Braille, and be mounted on the latch side of the door.  The entrance must have a clear opening of 32 inches and include maneuvering clearance adjacent to the push and pull side of the door conforming to the Maneuver Space Diagram.  In the interior of a multi-fixture bathroom, there must be a clear floor space having a minimum diameter of 60 inches to allow for turning around. Where there is a privacy wall in a bathroom, there must be a minimum of a 60-inch diameter clear floor space for turning.



There must be sufficient clear floor space surrounding the lavatory to allow for a forward approach (i. e., 48 inches clear from the wall where the lavatory is attached to approach and 30 inches of clearance from side to side). The lavatory is to be mounted so that the counter surface is no higher than 34 inches. The lavatory must extend out at least 17 inches with a clearance space under the lavatory of at least 29 inches. The drainpipe is to be mounted so that there is at least 9 inches of clearance from the floor surface. Insulation or other protective covering is to be used on the hot water and drainpipes under the lavatory to prevent contact. By a hand lever, push button or electronic control.



Faucets must be controlled by a hand lever, push button, or electronic control which is easily operated by one hand, does not require tight grasping, pinching, or twisting, and uses a maximum of 5 pounds of force for operation. Self-closing valves are to stay open for a minimum of 10 seconds.   Bathroom dispensers and accessories must be mounted so the highest control or operable part is no more than 48 inches high. Dispensers, which can be reached from a parallel/side approach, are to be mounted so that the highest operable control is no more than 54 inches high. The bathroom mirror must be mounted at a maximum height of 40 inches from the floor to the bottom edge of the reflective surface. The toilet paper and seat cover dispensers are to be located within easy reach of the person using the toilet. The toilet paper dispenser must permit delivery of a continuous flow of paper and be mounted at a minimum height of 19 inches.


Toilet Stalls:

At least one bathroom stall must be available that has a clear opening of 32 inches. The stall doors are to swing outward. The standard, accessible stall provides a minimum depth of 56 inches and a width of 60 inches for wall mounted toilets. Add 3 inches to the depth if the toilet is floor mounted. Where a standard, accessible stall is technically infeasible, an alternate stall must be provided. The guidelines provides two alternative plans for toilet stalls:

A.  For stalls allowing a forward approach to the toilet, there must be a minimum width of 36 inches and grab bars mounted on both sides of the stall.

B.  For stalls allowing a side approach to the toilet, there must be a minimum width of 48 inches and grab bars mounted to the side and rear of the toilet.

When a side transfer in a stall is required, two grab bars (a minimum of 42 inch long bar if it is mounted to the side and 36 inches long if mounted on the back) are to be mounted 33 to 36 inches from the floor. The diameter of each grab bar is 1-1/4 to 1-1/2 inches and the space between the wall and the grab bar is 1-1/2 inches. The grab bar must support 250 pounds. If there are six or more stalls; one additional stall must be provided that is 36 inches wide with grab bars on both sides.  The top of the toilet seat is required to be 17 to 19 inches from the floor surface. The center of the toilet must allow 18 inches from both sides of the stall. The flush controls are to be mounted no higher than 44 inches. They are to be operable with one hand and not require tight grasping, pinching, or twisting of the wrist, or more than 5 pounds of force. A men's bathroom is required to have at least one stall-type or wall-hung urinal with an elongated rim mounted at a maximum height of 17 inches.  For more information see:


Uniform Federal Accessibility Standards (UFAS)


What are the Mounting Heights for Grab Bars?

DHI Information (using ANSI/ICC A117.1-1998: Accessible and Usable Buildings and



What are Door and Hardware Code Requirements for Fire-Rating?  

How to choose the Right Fire-Rated Door?

Check the local building code and the authority having jurisdiction to determine the rating of the fire door you need.

Fire Label: Will need to be attached.  This is the agency approved certified or labeled doors, frames, and anchors for minimum ratings required by code.

Fire Ratings by Hour & by Letter-Designation:

Class "A" (3-hour)-Openings in firewalls that divide a single building into fire areas.

Class "B" (1 hour)-Openings in enclosures of vertical shafts and stairwells through buildings and in 2 hour rated partitions providing horizontal fire separations

Class "C" (3/4 hour) - Openings in walls or partitions between rooms and corridors having a fire resistance rating of 1 hour or less.

Class "D" (1 1/2 hour) - Openings in exterior walls subject to severe fire exposure from outside the building.

Class "E" (3/4 hour) - Openings in exterior walls subject to moderate or light fire exposure from the outside of the building.

No letter designation (1/2 or 1/3 hour) - Openings in walls or partitions between rooms and corridors having a fire resistance rating of 1 hour or less. Note that these doors are not really considered fire doors, but rather used for smoke control only.


What is the Largest Size of Visible Glass That Can Be Put Into A Fire-Rated Door?  

The required hourly rating will dictate the approved glass lites available. All glass used in fire rated doors must be listed glass, and be either 1/4" wire or other listed material. Basic guidelines on glass are as follows:

20 minute - 1296 sq. in. per lite with neither dimension exceeding 54"

3/4 hour - 1296 sq. in. per lite with neither dimension exceeding 54"

1 1/2 hour - 100 sq. in. per door leaf maximum

3 hour - flush door, no glass

See information from Von Duprin for fire and life safety codes for exit devices: Exit Door Hardware & Life Safety


Which is Best to Use--Welded or Knock-Down (KD) Frames?

Hollow metal frames come in two types: fully welded and knock-down (KD). Welded frames come in a single piece with all corners welded and ground smooth. This type of frame is positioned first and partitions (gypsum board on metal studs or masonry) are built to it. KD frames come in three pieces--two jambs and then the head and are they are installed after the partitions are in place; this type of frame is usually used with drywall construction only and is not durable as the welded frames. Both types can be used where a fire-rating is needed. 


What are the Rough Opening sizes on Knock-Down and Welded Frames:

Opening Size is the size of a frame opening, measured horizontally between jamb rabbets and vertically between the head rabbet and the finished floor. The opening size is usually the nominal door size, and is equal to the actual door size plus clearances and threshold height. 


Rough Opening is the wall opening into which a frame or is to be installed. Hollow metal frames come in two types: fully welded and knock-down. Welded frames are in a single piece with all the corners welded and ground smooth. Knock-down frames are in three pieces (two jambs and a head) and are installed after the partitions are in place (this type of frame is generally used with drywall construction only and is less cost effective than the welded frames). Both knock-down and welded frames can be used in fire-rated assemblies. Rough opening size for a knock-down frame-- add 1" to the nominal height and 2" to the nominal width.  (3070 knock down frame is 38" X 85"). Rough opening size for a welded frame: For a welded frame, add 2-1/4" to the nominal height and 4-1/4" to the nominal width.

(3070 welded frame is 40 3/8" X 86 1/8"). 


What is the Difference Between Fail-Safe and Fail-Secure Hardware?

The difference is whether or not the lock requires power to activate it or to release it. Fail-safe is when the door unlocks when the power fails. Therefore power is required to keep the door locked. The opposite is true of fail-secure. Fail-secure is when the door is secure and cannot be opened when power is removed or disconnected. This means that power must be applied in order to operate the lock.


Magnetic locks:

Magnetic locks work with DC current, usually 12 to 24 volts.

All magnetic locks are fail-safe and need a constant power source if they are to remain locked.  It is usually best to use a backup power source with magnetic locks. 

All magnetic locks are silent even when powered and locked. Make sure the magnetic locks are installed correctly so that they do not cause a fire hazard.


Electric strikes:
Electric strikes can be 12 or 24 or even a higher voltage and they may take AC or DC current or both. Electric strikes may be fail-safe or fail secure. As stated above, a fail-safe electric strike needs power in order to stay locked. A fail secure electric strike stays on with or without power.  


What Advantages do Continuous Hinges offer over Conventional Hinges?

Continuous hinges have distinct advantages over the use of several shorter hinges. Cut to match the full length of the door or lid to be hinged, continuous hinges are an integrated, rigid unit which provides support along the whole length, which guarantees that the door and frame are kept in perfect alignment and the hinge helps evenly distribute the load over the whole length or height of the door. Continuous hinges also:

  • Put the door and frame in a position where the force of opening and closing the door is dissipated along the length of  the door and frame preventing wear on any one particular area of the hinge. 
  • Have uniform strength throughout the entire length of the door.Have Smooth pivot action.
  • Can be made of almost any materialsteel, stainless steel, aluminum, and brass.
  • Have no exposed hardware
  • Are designed to make them less susceptible to the weather and tampering as well there is generally a noise reduction over conventional hinges. 
  • Require no special customization or reinforcements are necessary in doors and frames
  • Can be installed on existing doors and frames easily and economically. 
  •  Have longer life.  The continuous hinges are superior and longer lasting than tradition butt hinges. 

What Types of Electronic Access Control Systems are Available?   

Electronic Access Control Systems control the flow of people in and out of secured areas. Typical access control applications include a reader at the secured door, a door locking mechanism, and a door status indicator.  The reader at the secured door can consist of a variety of technologies including: active or passive proximity, Wiegand, smart cards, magnetic stripe, bar code, and others.  Higher security areas may require the use of biometric readers, which utilizes a biometric token to grant or deny access. Biometric technologies include: fingerprint, hand geometry, iris, retina, and facial recognition readers and systems.  Access to the secured area is typically granted based upon location, day of the week, and time of day. Alarms can be generated and operators notified of any invalid or improper access attempts by an individual or by a vehicle. 


Door Access Control Features

  • Each door can have separate open/close parameters.
  • Each entrant can have separate door access parameters.
  • Most systems allow the operator to make, via controlling software, separate open/close parameters for day of the week, weekend, etc.
  • Doors can be controlled at a single networked PC.
    Instant access to door access information, data can be used for attendance reporting.
  • Flexible design and custom solutions

Access Control Hardware

Magnetic Locks

The door is normally closed and secured by an electromagnetic lock. The lock is released from the interior by a touch sensitive exit bar or other type of request to exit device during door closed periods. A vandal resistant slot scanner, keypad or proximity reader releases the lock from the exterior with the authorized release of magnetic lock from the PC controller or supervisor override.


Electric Strike

The door is normally closed and secured by a door lock. The door is released manually from the interior during open and closed periods. The door is manually released from the exterior during open periods and manually opened during locked periods by an authorized release of the magnetic strike via the PC Controller or a supervisor override.


Electronic Door Knob

The door is normally closed and secured by a door lock. The door is released manually from the interior during open and closed periods. The door is manually released from the exterior during open periods and manually opened during locked periods by an authorized release of the magnetic strike via the PC Controller or a supervisor override.


Closed Circuit Surveillance Systems - These systems are used to view and record activity from remote locations and consist of a variety of components based upon the application. Typical components consist of cameras, monitors, multiplexors, switchers, recorders, and video transmission systems.

Cameras can be provided to meet a variety of needs. Low light, high-resolution, low-resolution. Other camera types are available to meet specific application needs.

Multiplexors provide the ability for multiple video images to be displayed on a single monitor. This reduces equipment cost and space required for multiple monitors.

Video switchers provide the ability to control multiple cameras and monitors. Large video installations may have hundreds of cameras and many monitors. Video switchers provide the ability for selected camera images to be displayed on specified monitors to better control the security environment.

Video recorders include the more traditional tape video recorder that records video images on demand or upon an alarm condition. These images can be recorded in real-time or in time-lapse mode.

Digital video recorders

These systems digitally record images on a computer's storage disks. When compared to the tape video recorder, this technology is more reliable due to fewer mechanical mechanisms that can fail. - Digital recorders contain no tape to replace or heads to wear out. They can use either an internal or external hard drive, they can have hot-swappable, redundant hard drives, and they can also employee CDR technology to make copies of images off of the hard drive for review. Video digital recorders also provide a greater degree of flexibility when searching and retrieving specific video images.  A variety of video transmission systems are available to transport the video image to a location for viewing or recording. These systems can include fiber, traditional telephone lines, LAN/WAN, and others.


Intercom & Telephone Entry Systems - Intercom systems communicate from distant locations to a central control center. For example, if someone is attempting to gain access to a secured area without access control, or if access control is present and his/her card was lost or forgotten, the individual could activate the intercom system to the central control center to request entry. Intercom systems provide two-way communications between the control and remote stations. Intercom can also provide video if required.  Telephone entry systems can be used in an environment such as an apartment or condominium complex.  The Telephone hardware is installed and connected to a telephone line.  The person requiring entry then uses the telephone to call a number pre-programmed into the Telephone entry system.  They are then connected via the telephone line and the resident or business that is called can then press a programmed number that then releases the lock at the door.  If they do not want to let the caller in, they merely need to hang up.


ID Badging Systems - ID badging systems are typically part of the access control system, but could be standalone as well. Badging systems allow the user to capture a video image of an individual, store the image, and print the image to an ID or access card using a thermal imaging printer.  The image can be either stored and later retrieved to print another card or retrieved for management purposes.  It can also be called up and compared if the user loses or misplaces a card and need to be identified prior to being allowed access to a controlled area.  The system allows for the creation of unique access or ID cards including: company logos, cardholder name, department names, etc.


Fiber Optic Security Networks - Fiber Optic technology is a method of transmitting information using pulses of light.  Fiber optic technology sends data without electricity through a conductor. Instead of electrical signals, modulated light is used to quickly transmit data over distances through an insulated glass fiber-type material. Fiber optics is currently the best communications method because it provides much faster data transfer speeds when compared to traditional interconnection media such as copper wire. The signal cannot be disrupted by outside sources like electricity, rain, humidity, or other things that tend to damage conventional copper wire signals. Fiber Optic Cables are ideal for volatile environments because there is no fear of damage should they break like there is with traditional copper wiring. Optical Fiber is lightweight compared to copper cabling because it is a thin glass strand. Security systems (access control, intrusion detection, and video) can communicate via fiber optic networks. These networks are off-the-shelf technology and are not proprietary to the system. This allows the user to take complete advantage of existing fiber backbones and the capabilities of the fiber technology 


Smart Card Technologies - Up to now, Smart Card acceptance in the US has been slow due to the lack of "sophisticated" applications. Now, with applications such as: e-Business Transactions, Secure Network Access, and Information Security, there will be an increased demand for Smart Cards. These applications are referred to as "logical" applications, whereas the more traditional access control cards are referred to as "physical" applications.


Networked Security Applications (LAN/WAN) - Security systems (access control, intrusion detection, and video) can communicate via LAN/WAN networks. There is off-the-shelf technology, as well as technology that may be proprietary to the system. This allows the user to take complete advantage of existing LAN/WAN backbones and capabilities of network technology.


What are the Wall Backing Requirements for Washroom or Toilet Partitions and Accessories?

Toilet partitions must have both floor-to-ceiling and wall bracing. Wall backing

in all rest rooms should be water-resistant plywood, water-resistant gypsum

board, or DuRock (or equal). Urinal screens shall have floor to ceiling pilaster

support. Check line of sight from entry door to urinals and to mirror reflections.

" Partition supports and pilasters should at least be specified for floor and wall attachment. Additionally attach to ceiling bracing if possible. Partitions which are attached only to the ceiling and walls should be avoided. Provide anti-grip type overhead braces over door openings.

Pilaster shoes and caps should be attached with manufactured clips.

" All fasteners and assembly screws shall be tamper proof. Partitions shall be attached to the wall with no less than three brackets. Brackets shall be secured with no less than two fasteners. All hardware shall be heavy-duty institutional type. Door hinges shall be adjustable self-closing.

" Doors on HC stalls shall be out-swinging. Doors on regular stalls shall be in-swinging. Provide pulls on both sides of out-swinging doors to handicap stalls.


How do I hand a door?  

The hand of any door is always determined from the entrance or the outside of the opening to which the door is applied.


See Door Handing