I attended one of my favorite customer’s 75th anniversary party last week. While mingling I met an architect and the conversation drifted to hardware. As always when I meet an architect the question I ask is what frustrates you most about hardware?
In this case the answer was the different grades of locksets. The architect went on to explain that he primarily uses mortise locksets but he knows they are the "top of the line" and sometimes his clients prefer something less so.
As I was explaining the different grades and how he might be able to value engineer I thought this information might make a good blog post. Aren’t bloggers always thinking that!
The Builder’s Hardware Association (BHMA) and the American National Standards Institute (ANSI) developed grading requirements for cylindrical and mortise locksets to ensure quality and performance from builders hardware.
Strength, performance, and construction are all included in defining the three grades of locks.
|Hager Grade 1 3400 Lock|
Grade 1 is the highest performing rating. A Grade 1 lock must be capable of performing through 800,000 latches and unlatches without failure. It must withstand 700 lbs of force per inch for lever locks.
Grade 2 is a medium grade and capable of operating through 400,000 cycles while withstanding 450 lbs of force per inch for lever locks.
Grade 3 is the lowest grade. It must operate for a minimum of 200,000 cycles and withstand 225 lbs of force per inch for lever locks.
In my opinion how to choose what Grade of lock is appropriate is less about the building and more about each individual door opening. After reviewing specifications for 19 years I know Grade 1 is the most popular choice. These locks should be used on exterior openings that don’t require an exit device and any interior opening that gets heavy traffic but there are other less used openings in a building that a Grade 2 lock may be used and in turn save the owner money. I haven’t yet used a Grade 3 lock in a commercial application.
A couple of examples:
Locksets at schools get a lot of abuse! Every exterior opening should have Grade 1 hardware both for security and abuse factors. Any interior openings at middle and high school that kids use should also have Grade 1 hardware. What kids can do to a lock never ceases to amaze me. However at a single bathroom in the teacher’s lounge a Grade 2 might be acceptable.
In another scenario a Grade 1 lock at the entry doors into a tenant space in an office building is a smart choice for security. The offices, bathrooms and storage rooms, depending upon the tenant employee/visitor numbers, a Grade 2 would be a good choice.
Manufacturers typically offer the same lever & rose styles for both Grade 1 and 2 locksets so all the locksets will be uniformed even when mixing different Grades.
There is a lot more information available but hopefully this provides a basic outline for you.