What are the two main types of standpipe systems?

The correct answer identifies the two main types of standpipe systems: wet standpipe systems and dry standpipe systems. A wet standpipe system is a type that is constantly charged with water, ensuring that firefighters have immediate access to water for firefighting operations. This is particularly beneficial in buildings where there is a consistent risk of fire, as it allows for quick response times in emergency situations.

On the other hand, a dry standpipe system does not hold water in the pipes unless needed for firefighting. Instead, it remains empty until firefighters connect a hose and supply water through the system. This is commonly used in areas where water could potentially freeze or in climates that are extremely cold, thereby preventing damage to the piping.

Understanding the distinction between these two types of systems is critical for effective emergency response and planning in fire protection strategies. The other answer options focus on various aspects of standpipe systems but do not categorize them in the same way. For instance, active and passive systems refer to broader fire protection strategies, while classifications like high-rise versus low-rise pertain more to the building's height and associated challenges rather than the types of standpipe systems themselves.