<P> Intumescent firestops are often used, in the event plastic pipes are used for toilet drains, so that the melting plastic pipe is choked off in the event of an accidental fire . It is, however, customary to fill the metallic drain pipe annulus with rockwool packing . Even with the best of intentions, it would be difficult for the firestopper to install a sealant, because the installer is not allowed to remove the flange, which is partially used to support the drain pipe below during the installation process . </P> <P> Studies have shown aerosol droplets are produced by flushing the toilet, that enter the air of the room . No proven cases of infection have been found, and the risk is unknown . A Fecal - oral route was demonstrated for aerosol droplets that are produced by flushing the toilet . These aerosols are also called "toilet plume". </P> <P> If clogging occurs, it is usually the result of an attempt to flush unsuitable items, or too much toilet paper . Flushing of large amounts of hair should also be avoided . However, clogging can occur spontaneously due to limescale fouling of the drain pipe, or by overloading the stool capacity of the toilet . Stool capacity varies among toilet designs and is based on the size of the drainage pipe, the capacity of the water tank, the velocity of a flush, and the method by which the water attempts to vacate the bowl of its contents . The size and consistency of the stool is also a contributing, but hard - to - predict factor . </P> <P> In some countries, clogging has become more frequent due to regulations that require the use of small - tanked low - flush toilets in attempt to conserve water . Sometimes, three to four flushes periodically during the use of a low - flush toilet may be required to prevent clogging, thus using more water than larger - tanked toilets . Designs which increase the velocity of flushed water or improve the travel path can improve low - flow reliability . </P>

When was the first flush toilet installed in the white house