Commercial door knob terminology?

I'm trying to replace my front door knob with a commercial knob for better security and the ability to use SFIC interchangeable lock cores. I am unfamiliar with the terminology they use. I bought a Dexter brand knob that says "Function: Entry/Office".

It works, but the problem is even if it is locked, the knob on the inside still turns. This makes it very easy to accidentally lock myself out! Is there a different "function" knob in which the inside handle will not turn when the lock is engaged? I don't understand the differences between those labeled office, classroom, storeroom, etc.

Or, might it be possible to modify the knob I already have not to be this way?

 

Dexter is made by Schlage and this is how their keyed entry knobs work.

 

Is that not part of the "function" terminology? For example, I believe a "storeroom" knob stays locked at all times, even after you open it with a key. (though I could be wrong) What is the difference between "entry, office, classroom, storeroom", etc? They all basically look the same.

I imagine this has something to do with commercial fire codes, but there is no reason I need a knob marked "entry", all I care about is if it stays locked on both sides. It doesn't matter what brand it is.

 

You are correct, the "Function" describes the operation of the lock. Specific Function numbers are assigned to locks by the American National Standards Institute (ANSI), however each manufacturer is at liberty to use a descriptive term to describe the operation. Most of the time they all agree on the terminology, but not always. Generally, the "Entry" function has a key outside and a button/thumbturn inside, but with one manufacturer, the button locks both knobs, but with the other one, it doesn't.

AFAIK, the function you're looking for does not exist in commercial-grade locks, because for a basic Entry function, they don't meet fire codes requiring a single action to exit. Residential codes, being not as strict, have allowed this function, at least in the past. And the only reason you find these locks at all is because it's cheaper to make them this way. The #1 Residential Entry lock in the USA is the Kwikset Tylo because of low cost.

(cont)

 

Two ways to accomplish what you want, the first is the safest and cheapest:

1) Put a single-cylinder deadbolt in the door and replace the entry lock with a "Passage" (non-locking) Function of your choice. You won't lock yourself out, and you'll have far better security. And, of course, Grade 1 and Grade 2 deadbolts are available for SFIC.

2) Schlage (and others) make an ANSI "F91" Function which they call a "Store Door" Lock, part number: D66PD. It'a a cylindrical prep. lock with key both sides, in which the key locks or unlocks both sides from either side. Of course, to mimic the function you want, you'd have to leave the key in the inner knob. This is not a good solution for obvious life-safety reasons, plus it's a high cost Grade 1 only, and a special-order 2-3/8" latch would be needed for a residential backset prep.

 

While we're on the subject of Terminology, it might be helpful to review a lock's "Grade" designation, which is showing up now on consumer packaging.

This is an Underwriters Laboratories (U/L) listing in which the lock is tested for durability, finish, and integrity. It's not the end-all/be-all when deciding what lock to purchase, but it's a general guide to it's intended use.

Grade 1: Heavy Duty Commercial/Industrial use. Full range of Functions, finishes and designs.

Grade 2: Medium Duty, Light Commercial and Heavy-Duty Residential. Modest range of Functions, Finishes and Designs.

Grade 3: Light Duty Residential only. Usually only available in Passage, Privacy and Entry Functions. Few Designs and Finishes.

 

Hmmm...I thought about using the deadbolt only, but I'd really like both of them to be lockable. I travel a lot and it's not uncommon for my house to be empty for a week or two. Do you know if anybody makes the "store door" style with SFIC locks? If I could find a knob with SFIC on both sides, then they make SFIC thumb turns that fit into the hole, no key required. The only ones I can find in google look like they all use the KIK style cores, which wouldn't match all my other locks. (I'm trying to key everything I have to one key)

 

The D66BD (knob) as well as the newer ND66BD (Lever) are SFIC ready. (The "B" in the part number is for Best). The thumbturns I've seen tho, are plastic, designed for temporary use during construction, but maybe they make a more permanent metal version, I don't know. Be prepared to pay with your first-born, compared to the Dexter; they ain't cheap.