When you own or manage any type of commercial facility, caution is needed when hiring security personnel, as you are often legally liable for any actions your security personnel take while on the job. In turn, you need to ensure you hire someone who can provide actual security while still keeping the facility safe, and that includes ensuring safety from intruders, thieves, intoxicated employees, and the like. Note a few key questions you might ask when interviewing potential security guards for your facility so you can get a good idea of their temperament and personality and potential job performance.
Ask how they would talk to an angry person
This is a very important question to cover, as security guards often deal with angry complainants as well as those suspected of doing something wrong. For example, if one of your staff members calls security to report their wallet as stolen or that their car has been vandalized, they may take their anger and frustration out on the security guard. If your security personnel need to question someone they suspect of stealing, that person may be angry at simply having been accused, even if they didn't do anything wrong. If a security guard cannot remain calm under this type of duress, they are not the right person for working security in a commercial facility.
Ask how they would break up a fight
Even in an office or warehouse, two co-workers may come to blows over a disagreement, accusation, or anything else that would otherwise seem relatively minor. In a place that is open to the public, it's also very possible for two customers to begin fighting for a variety of reasons. Your security personnel should know how to calmly break up such an altercation so as to reduce the risk of injuries and also ensure that this also doesn't escalate into something more serious.
Ask how they respond to another officer sleeping on the job
If security personnel work at night, it's not unusual for them to be fighting fatigue. However, they do need to stay awake and alert in order to do their job, and you may want to ensure that your security staff are willing to report any incidents involving another officer. This can include catching someone sleeping, being away from their post, being intoxicated, using company equipment for personal use, and so on. If a potential security officer is hesitant about this question, that might tell you that they would overlook these issues, and they may not be a good fit for your company.