A lot of the cameras available will be good for this task - normal fixed lenses will be designed for mid to long range focus, and even non radiometric imagers (a thermal image, but not a temperature readout) and low resolution/framerate cameras will still give you good identification of problem spots. The tier up of available cameras will probably have manual focus lenses (look at datasheet specs for near focus distance if up close work is important to you), and if you were wondering, auto focus is not really a thing in thermal cameras.
You will probably end up with a 9Hz update rate on the thermal core, as they aren't export restricted, but you want to look for something with a reasonable thermal sensor resolution for the price (sometimes they advertise screen resolution and hide it in a spec sheet), and something that produces good looking images (looking them up here or elsewhere should give you an idea). A lot of the similar price class units available use the same core, so you can expect some degree of performance parity among competing products in some cases, so looking for additional features could help set one apart. FLIR has things like MSX (other brands have to call it something else), that basically takes edge data from a visible light camera and adds it to the thermal image to give you a sort of enhanced resolution, and especially with lower resolution sensors, it can be handy to keep your landmarks straight when looking at the image. You probably want a handheld unit with controls, unless you think a phone dongle fits your use case, but a standalone thermal core could conceivably do the same job.