4. Routine maintenance, inspection and operational testing of the emergency generator and associated. components must be overseen by a properly trained person [see MSFC(07), Sec. 604.5; NFPA. 99(99), Sec. 3-4.4.1.1(b)3; NFPA 110(99), Sec. 6-4.7; NFPA 110(02), Sec. 8.4.7].
If rain and wet roads are a concern, you should consider replacing your tires when they reach approximately 4/32 of remaining tread depth. Since water can't be compressed, you need enough tread depth to allow it to escape through the tire's grooves.f two of your tires have a lot of remaining tread depth, but you need to replace the other two because they were damaged or have worn out, you should replace them with a pair of tires that come as close as possible to matching your existing tires.
You can make sure that the tread on your existing tires is safe by checking it at least once a month when you check your tires' air pressure. Start by culling out the riskiest rubber. Look for bald tires by checking whether any of the wear bars are flush with the tread's outer surface. Another way to check whether your vehicle's tires have reached their wear limit is to insert a penny into each groove, Lincoln's head down, as shown below. Replace the tire if the top of Abe's head becomes uncovered by any of the grooves.