Universal columns are the most often used section for structural steel purposes. Unlike a universal beam, the UC’s width is roughly equal to their depth. For example, a 152 UC 23 is 152 mm wide and 152 mm deep. The last number (23 in this example) is the weight per metre in kilograms. It is therefore easy to work out what is the total weight of a UC by simply multiplying its weight per metre by the total length in metres. You may find two numbers before the UC abbreviation, eg. 152 x 152 UC 23, however in most cases one of them is omitted as they are both the same. Universal columns are mainly used for columns, however their small depth compared to universal beams make them ideal load bearing members when height is limited (which is quite often the case in residential projects).

Similarly to universal columns, universal beam are referred to as “I-sections” or “H-sections”. The depth of a UB is greater than its width and difference is quite big, making it easy to spot. The increased depth results in higher loading capabilities than UCs, however there is not always enough space to use a UB. An example is a 203 x 133 UB 30. The first number is the depth of the beam, the second is the width and the last number is the weight (in this case 30) per metre in kilograms. Again, by multiplying the total beam length in metres by the weight per metre we can quickly work out what is the total weight of the beam.

Parallel flange channel is normally called a channel or a “C-section”. They are described by their depth, width and weight per metre in kilograms, eg. 150 x 75 x 18 PFC. The PFC is used for columns, lintels above doors or simply a beam supporting floor joists. When used for lintels, they have a bottom plate welded to it that takes the outer bricks or 2 channels are bolted back to back with 100 mm spacers to support both leafs of a cavity wall.

Type	Weight [kg/m]	Height [mm]	Width [mm]	Web thickness [mm]	Flange thickness [mm]
100 x 50 x 10 PFC	10.2	100	50	5.0	8.5
125 x 65 x 15 PFC	14.8	125	65	5.5	9.5
150 x 75 x 18 PFC	17.9	150	75	5.5	10.0
150 x 90 x 24 PFC	23.9	150	90	6.5	12.0
180 x 75 x 20 PFC	20.3	180	75	6.0	10.5
180 x 90 x 26 PFC	26.1	180	90	6.5	12.5
200 x 75 x 23 PFC	23.4	200	75	6.0	12.5

UPN Channels –Europian Standard Channels .

Eg: UPN 80 Channel or UPN 80 x 20 x 6 means … 80 mm web height,20 mm flange height and 6 Kg weight per meter.

Rectangular hollow sections are not as common as UCs and UBs. This is down to the fact that it is much more difficult to bolts it to other beams or to bolt other members to it. RHSs are described by their depth, width and wall thickness. An example is a 200 x 100 x 8 RHS, which is 200 mm deep, 100 mm wide and the wall is 8 mm thick. Hot rolled RHSs are made at the mill as one piece, whereas cold formed RHSs are made of a flat sheet rolled at right angles and welded. It is therefore easy to note the difference, as the cold rolled RHSs have a weld all along its length.

Square hollow sections are often used for columns, however similarly to RHS sections, they are not often used as beams due to its shape that makes it difficult to bolt to other beams and vice versa. SHSs are often called “box sections”. An example is 100 x 100 x 10 SHS, which is 100 mm deep, 100 mm wide and the wall is 10 mm thick. Similarly to RHS sections, hot rolled SHSs are made at the mill as one piece, whereas cold formed SHSs are made of a flat sheet rolled at right angles and welded. It is therefore easy to note the difference, as the cold rolled SHSs have a weld all along its length.

Circular hollow sections are used as columns and braces in portal frames structures. An example is a 114.3 x 5 CHS, which has a diameter of 114.3 mm and the wall is 5 mm thick. . Similarly to RHS and SHS sections, hot rolled CHSs are made at the mill as one piece, whereas cold formed CHSs are made of a flat sheet rolled at a radius and welded. It is therefore easy to note the difference, as the cold rolled CHSs have a weld all along its length.

Rolled steel angle – equal is normally called an “angle”, “equal angle” or “L-shape”. Even though both legs are the same length, they are described by giving both leg lengths and the wall thickness (all in mm), eg. 100 x 100 x 12 RSA. For structural steel purposes, equal angles are most often used for brackets for cleat connections. Sometimes they are also used as lintels (2 angles bolted back to back). They are often used for balconies, platforms, stairs, concrete supports, etc.

Rolled steel angle – unequal are called “angle” or “L-shape”. The are described by giving both leg lengths (longer first) and the wall thickness (all in mm), eg. 150 x 100 x 8 RSA. With the longer leg being in a vertical position, its loading capabilities are greater than equal angles, therefore they are often used as lintels. Unequal angles are also used as brackets for cleat connections. Similarly to equal angles, they are of the used for balconies, platforms, stairs, concrete supports, etc.

Flat sectionsare used anywhere where a connection between 2 beams is required. They are used for base plates, end plates, stiffeners, gussets, tabs, splice plates and many more. In some cases they add strength to a beam when welded along the length of a beam (top or bottom). Flat sections are described by its width and thickness, eg. 200 x 12 Flat (both in mm). When a flat section is cut to smaller pieces, then they are called “plates”. Sometimes flat sections are used to reinforce timber joists (“flitch beam”) by bolting it to the joist every 400 – 600 mm.