This section is from the book "A Treatise On Architecture And Building Construction Vol3: Stair Building, Ornamental Ironwork, Roofing, Sheet-Metal Work, Electric-Light Wiring And Bellwork", by The Colliery Engineer Co.. Also available from Amazon: A Treatise On Architecture And Building Construction.
53. Conductors, or leaders, as they are often called, are the pipes which conduct or lead away the water from the gutters. They may be classed as inside or outside leaders. Inside leaders will be treated in Plumbing and Gas-Fitting.
Outside leaders are fitted up against the outside of the building. They are made in many shapes and of different metals. Fig. 43 shows the round-pipe leader as usually erected. These leaders are usually made of tin by the tinsmith, who also makes the elbows a, a, a, which, usually, are altogether too sharp. Tin straps b, b are soldered to the leader at intervals of about 6 or 8 feet and are nailed to the walls, as shown. Round leaders are not suitable for outside service in cold climates because they persistently freeze and burst.
Fig. 43 illustrates an ever recurring spectacle in cold weather, when snow lies on the roof, and the temperature of the air is below freezing point. The sun shines on the roof, but not on the leader. The snow on the roof melts and the water trickles down the leader, and, by the time it nearly reaches the bottom, it becomes frozen to the sides of the leader. This ice slowly thickens until the leader is entirely choked at that point which, in Fig. 43, is the lowest elbow.
The remainder of the melted snow then gathers in the leader and fills it. This water now solidifies and bursts the leader as shown. The pipe has burst because it could not stretch enough to accommodate the increase in volume of the water as it was changed into ice.