Which additives may be used to stop minor leaks in the standpipe system?

Sodium silicate or brine is utilized to stop minor leaks in standpipe systems due to its properties as a sealing agent. Sodium silicate is often referred to as "water glass" and can create a gel-like structure when it comes into contact with water. This property allows it to fill gaps and cracks, effectively sealing off leaks. The brine component can enhance the sealing capabilities by introducing a viscous fluid that can flow into leaks and reinforce the waterproof barrier.

Using sodium silicate, especially in fire protection systems like standpipes, is advantageous because it can help restore the integrity of the system without requiring extensive repairs. The compounds are compatible with the materials typically used in fire protection piping, ensuring that they do not cause additional harm while they seal.

Other options, such as potassium chloride, calcium carbonate, and magnesium sulfate, do not possess the same sealing properties and are not commonly used for minor leak repair in standpipe systems. These substances may serve different purposes but lack the ability to effectively fill and seal leaks in the context of fire suppression systems.