Generally speaking commercial locks are purchased from locksmiths or service centers.
This is because of the higher cost of the locks, the additional keying requirements that might be needed and installation services.
Now that you know where to get them what is the difference between residential and commercial locks?

• Commercial locks are ANSI Grade 1 or 2
• They are heavier duty made with commercial grade parts
• They typically will have a higher number of master keying capabilities
• They are designed to fit a larger range of doors with different thicknesses
• They can interact and work with electronic door locks
• Upgraded finishes with increased colors

To better understand this I am going to explain in a little more detail what the ANSI/BHMA grades are.
First ANSI stands for American National Standards Institute, BHMA is (Builders Hardware Manufacturers Association).
The three grades are the same for both.
Here are some of the differences between grades:

• Cycles-Grade 1=1,000,000, Grade 2=800,000 and Grade 3=800,000
• Latchbolt Projection-Grade 1=3/4 inch, Grade 2=1/2 inch and Grade 3=1/2 inch
• Impact Test-Grade 1=10 blows, Grade 2=5 blows and Grade 3=2 blows

These are just some of the differences there is almost a dozen that grade sawing resistance, different impact tests, force to latch door and others.
The important thing to remember is that all locks are not created equal.
You will also find more high security lock cylinders used in commercial applications.
Most of these lock cylinders will be protected by U.
S.
patents.
This usually means that the cylinder is built to very high standards and they have very high key control.
This means that the keys are registered to a particular company and identification is needed to cut additional keys.
Key blanks are available at authorized service centers.
The master keying abilities are also increased with the ability to have multiple levels of a master system.
For example each floor of a commercial building could have its own master key with all the doors on that floor keyed different.
The master key will open all the doors on that floor.
There could be a grand master key that will open all the doors on every floor in the building.
Locks for commercial applications should be grade 1 or at least a higher quality grade 2.
These will stand up to the repeated use in commercial buildings and businesses.
It is also important to choose the right service center or locksmith that understand commercial locks and locking systems.