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].
Replace the tires at least every 6 years. If you're not sure, the minimum replacement time that is recommended by the NHTSA is six years regardless of use, with 10 years being the maximum service life for tires. Check your owner's manual for specific recommendations related to your car.s the tires wear, these bars will become flush (level or even) with the tire's tread. At this point, it's time to replace the tires. 3. Check the tread by using the penny test.  Take a penny, and place it upside down with Lincoln facing you in the center of the tread (at the thickest part of the tire).
The tread depth groove in the tyres will tell you when your tyres are at the bare legal minimum of 1.6mm, ideally you should change your tyres earlier. The best way to check you tread depth is to buy a tread depth gauge.The gauge will give you the exact amount of tread remaining and will a lot more accurate.ost tyres now also have a depth indicator as shown in the picture above. The depth indicator is placed around the tyre within the groove. This is an easy way to check your tread depth. Once this groove indicator levels off with the top the tread the tyres are at 1.6mm.