Answers to one of the most common questions about Builders Hardware.
The Builders Hardware Manufacturers Association (BHMA) has been in the business of developing and publishing American National Standards for hardware since 1983. Currently, 42 different standards cover products from locks to door closers to exit devices. As a whole, the standards define all tests and characteristics necessary to ensure products will reliably perform as expected. The “duties” of selected hardware have been summarized as “hanging the door, controlling the door, and securing the door” with life safety, durability, aesthetic, and accessibility responsibilities.
To provide economical choices when selecting the right hardware for an application, most BHMA standards include a system of three grade levels to be assigned depending on the product’s ability to pass increasingly rigorous test requirements. Grade one is the highest performance, followed by grades two and three. The ANSI/BHMA grading system is useful for ensuring the most appropriate hardware is specified for each application. The expected usage and necessary security for the installation should be considered when deciding which grade will be needed.
To better understand how the grade of a given product is determined, it might be helpful to know some details of the process and requirements. For this illustration, we will use ANSI/BHMA A156.13 for Mortise Locks, a product typically used in commercial and institutional facilities. In this standard (and in most other lock standards), the tests are grouped into six categories: Operational, Cycle, Strength, Security, Material Evaluation, and Finish. The tests are all done in carefully controlled laboratory conditions with defined methods. Each is discussed below:
This includes tests that make sure the door will latch easily when pushed closed—all grades must be a maximum of 4.5 pounds force. Another test measures the force to retract the latch by lever, ensuring accessibility—all levers are required to retract with 28 inch-pounds or less rotational force.
Here, the lockset is installed on a mechanically operated test door and operated until the required cycles are obtained and then re-checked for operational compliance. The grade one test runs for one million cycles, grades two and three for 800,000.
Strength tests are meant to ensure the trim, latches, deadbolts, and lock mechanisms hold up to daily abuse, such as excessive forces on a lever, and still operate properly. For all the tests in this section, all grades must meet the same minimum of 360 pounds applied on top of the lever.
This array of tests could be described as attacks to gain entry. The differential between the grades can be fairly significant for them—for example, the test using a ram to impact the cylinder face is:
|75 ft.-lbf (100 J) 10 Blows
|75 ft.-lbf (100 J) 5 Blows
|75 ft.-lbf (100 J) 2 Blows
The trim must meet requirements such as an impact to the rose with a pointed probe. Here grade one is a little more “heavy duty” than grades two and three:
|Grades 2 and 3
|0.075 in. (1.9 mm)
|0.100 in. (2.5 mm)
This is a set of tests that ensures the lock will look acceptable after exposure to various environmental conditions. As is typical for most BHMA standards, all grades must meet the same requirements.
In the Mortise Lock Standard, it is permitted for a model to designate an Operational Grade (the minimum level met by all tests except security), which is different from the Security Grade.
With BHMA standards representing 42 types of hardware, differences in the requirements with respect to grading could be expected, but the preceding example is fairly representative.
Because these are laboratory tests, there is no absolute correlation to actual field performance, i.e. a product’s life span. However, BHMA standards are meant to ensure their respective builders hardware products are evaluated to meet the most challenging expectations in the built environment, and grades are provided to provide choices depending on the role of the hardware in the building. It may also be helpful to consult manufacturer literature for guidance.
Contributing Author: Michael Tierney, Product Standards Co-ordinator, Builders Hardware Manufacturers Association (BHMA)
Michael Tierney has served as the product standards co-ordinator for the Builders Hardware Manufacturers Association (BHMA) for 20 years, where he co-ordinates the development and revision of BHMA’s performance standards. Tierney came to BHMA following a 20-year career in manufacturing management at United Technologies, Honeywell, Black and Decker, and Yale Security. He is a principal member on technical committees for the National Fire Protection Association (NFPA), and the ICC A117.1 Committee for Accessible and Usable Buildings and Facilities. He also chairs the ANSI TAG 162 for Doors and Hardware. Tierney can be reached at firstname.lastname@example.org.