Sheet Metal, Level 2, 4th edition

Module ID 04301 - Field Measurements, Calculations, and Fittings

Mathematics represents the essence of the sheet

metal craft. Mastery of the mathematical calculations

needed often separates the skilled from

the unskilled. The math required of a sheet metal

craft professional is not abstract nor theoretical.

Instead, it is directly applied to solving work-related

problems and creating each workpiece.

Following a review of important mathematical

concepts, those same concepts will be applied in

this module to creating various offsets and seam

allowances. Unlike straight lengths of duct, offsets

must often be laid out based on field measurements

to fit a specific and unique situation. It is

essential that a craft worker learns how to take

measurements accurately and between the correct

points. (25 hours)

Module ID 04202 - Construction and Sheet Metal Drawings

By the time plans and specifications have made

their way to the construction site, they have been

subjected to considerable scrutiny. Their final form

is the result of numerous negotiations between the

building owner, architect, mechanical engineers,

estimators, and craft professionals to arrive at a

final system design. It is essential that the plans

and specifications are accurately interpreted.

Deviation from the plans or a misinterpretation

could result in having to demolish and reinstall

portions of a system that could lead to a significant

loss for the company. (17.5 hours)

Module ID 04203 - Radial Line Development

Radial line development is a sheet metal layout

method frequently used for the fabrication of fittings

such as cones, reducers, and other tapered

shapes. This module describes the principles of

radial line development and examines how to lay

out and fabricate various sheet metal components

using radial line development techniques. (55 hours)

Module ID 04306 - Triangulation

Triangulation is one of three methods used to lay

out and fabricate sheet metal fittings. More specifically,

it is the process of using trigonometry to

lay out patterns and calculate true line lengths. It

is often used to lay out some of the more difficult

fittings used by sheet metal workers, including

square-to-round fittings, roof collars, stacks and

caps, and fittings that join at unusual angles. This

module describes the triangulation process and

how it is used to develop patterns for fabricating

sheet metal duct fittings. (47.5 hours)

Module ID 04204 - Sheet Metal Duct

Fabrication Standards

To ensure a product of consistent quality and promote

professionalism in the craft, the sheet metal

industry requires standards that identify the best

way to fabricate and install ductwork. In addition

to industry standards, governments at the

local, state, and federal level develop and maintain

building codes in the interest of public safety.

While adherence to industry standards is largely

voluntary, contractors are legally obligated to follow

building codes. (7.5 hours)

Module ID 04206 - Bend Allowances

When metal is bent, a portion of the length of the

flat piece is consumed in the bend. Metal on the

inside of the bend is compressed, while the metal

on the outside is stretched. To make sure the final

piece has the proper dimensions after the bend, an

allowance must be added to the dimensions of the

stretchout to compensate for the distance around

the bend. (7.5 hours)

Module ID 04207 - Soldering

Soldering is a process in which a heated metal

alloy is used as a filler metal to fasten sheet metal

parts, seal seams, and connect piping. To do a professional

soldering job, craftsmen must know how

to prepare the material being soldered, choose the

appropriate materials, and use the required tools.

Because the soldering process involves chemicals

and hot surfaces, it can be hazardous. Craftworkers

must learn how to solder carefully and safely

while making effective, sound joints. Soldering is

a skill that requires practice as well as knowledge.

(15 hours)

Module ID 03109 - Air Distribution Systems

Most heating and cooling systems use ductwork

to deliver conditioned air to the spaces being

cooled or heated. The ductwork may be made of

sheet metal, fiberglass ductboard, fabric, or flexible

duct. The performance of an HVAC system

is closely linked to the quality of the air distribution

system. The ductwork must be of the proper

size and type, and must be correctly installed and

sealed. (15 hours)