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Gutters, scuppers and conductor heads · Lesson 2 of 4

Gutters, scuppers and conductor heads: materials, standards and design constraints

Copper weights, the materials and bend limits AFS works to, expansion joints, laps, slope and hangers by specification, GT-1, and how codes and rainfall data change by edition and place.

You will be able to: Read material weights from the specifications, check a gutter against what AFS can make, account for thermal movement, laps, slope and hangers, and name the tests and code sections that apply, edition by edition.

17 min · 12 slides · 16 questions

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Slide 1 of 12

Copper weights in the specifications

The CDA guide specification makes hung gutters and downspouts of 16 oz copper (0.0216 in) and built-in gutters of 20 oz copper (0.027 in).

The CDA sets 16 oz as the minimum copper weight for scuppers and for conductor heads.

These are guide specification values for copper, not code; the project specification governs.

AFS copper thickness by weight, with the CDA guide specification weights markedBar chart of the thickness in inches of the four copper weights on AFS's list: 16 oz 0.0216, 20 oz 0.027, 24 oz 0.0323 and 32 oz 0.0431. A steel blue marker beneath 16 oz and 20 oz shows the weights the CDA guide specification names: 16 oz for hung gutters and heads, 20 oz for built-in gutters.AFS copper: thickness by weight0 in0.010.020.030.040.050.021616 oz0.02720 oz0.032324 oz0.043132 ozCDA guide spec16 oz hung, 20 oz built-inAlso on AFS'scopper list

Bar chart of the thickness in inches of the four copper weights on AFS's list: 16 oz 0.0216, 20 oz 0.027, 24 oz 0.0323 and 32 oz 0.0431. A marker beneath 16 oz and 20 oz shows the weights the CDA guide specification names: 16 oz for hung gutters and heads, 20 oz for built-in gutters.

Thicknesses are from AFS's material register; the zero baseline is the axis. The CDA guide specification names only 16 oz (hung gutters, downspouts, scuppers and heads, as the minimum) and 20 oz (built-in gutters); 24 and 32 oz are also on AFS's list. The project specification governs.

Sources

Glossary

Guide specification
A model specification a designer edits for a project; its values are not code.
Expansion joint
A joint that lets a long gutter move with temperature; it also ends a drainage section.
SPRI GT-1
A laboratory test standard for the strength of external gutters under outward, upward and downward loads.
Secondary drainage
Overflow drains or scuppers that take water when the primary drainage is blocked.
Rainfall intensity
Rain depth per hour for a storm duration and return period at a location, read from NOAA Atlas 14.