Final answer:
True, Type L vents must not be used to vent coal- or wood-fired appliances as they are not suitable for the high temperatures and corrosives these fuels can produce.
Step-by-step explanation:
The statement 'Type L vents must not be used to vent coal- or wood-fired appliances' is true. Type L vents are typically used for venting oil-fired appliances and category I natural gas appliances. However, they are not suitable for coal- or wood-fired appliances, which produce higher temperatures and often contain corrosive materials that can degrade the vent.
True, Type L vents must not be used to vent coal- or wood-fired appliances as they are not suitable for the high temperatures and corrosives these fuels can produce. It is crucial to use the proper venting system designed for these types of appliances to ensure safety and efficiency. Moreover, following the manufacturer's instructions and ensuring proper ventilation when using any products that release pollutants into the indoor air is essential for maintaining indoor air quality.