all fire systems should be inspected after a certain time (usually annually).
Fire extinguishers must, by code, be recertified every year in most authorities having Jurisdiction. (AHJ)
Do Fire Extinguishers Expire?
Recent question from a veterinarian: “Do fire extinguishers ever expire? I've been here for 6yrs, and have never used them. They are both dry chemical extinguishers, if this makes any difference.”
What a great question! Fire extinguishers don’t normally expire, but some do need recharging occasionally. However, some professionals routinely start replacing or recharging extinguishers after about 7 years of service as a preventive measure.
This is why OSHA’s Fire Prevention standard requires all fire extinguishers to be "inspected" annually by someone trained to do that inspection. Most practices have their fire extinguishers inspected yearly by a safety company, which places month and year inspection tags on each extinguisher. The average cost for this service is only a few dollars per extinguisher.
In addition, OSHA also expects the business to regularly (like every month) check each fire extinguisher for leakage, damage, corrosion or other defects. This monthly check is also designed to ensure the extinguisher hasn’t been removed from the designated location for any reason. Although not required
by OSHA, we recommend a monthly check list like the example here.
Another good way to remember to do the checks is to use the reminder feature on the practice computer: set up a vaccination code for fire extinguishers with a monthly reminder frequency. The practice administrator can hand the reminder card to a staff member with an instruction sheet and the staff can share in these responsibilities. The staff member then “invoices” the clinic for the inspection through the computer.
There are many types of fire extinguishers; the most common is the dry chemical one. Other types include carbon dioxide and foam. The carbon dioxide extinguishers are very common in areas with electronics and computers since the dry chemical powder is corrosive to printed circuit boards. Foam extinguishers are generally used on chemical fires where sustained oxygen deprivation is required.
Each fire extinguisher is rated to suppress certain kinds of fires. Class A is general materials, B is chemical, C is electrical and D is flammable metals. Most extinguishers used in the veterinary practice are multi-rating, e.g, A-B-C.
Locate a professional (look in the telephone directory under Fire Extinguishers) for recommendations on a specific location.
Sources: My answer