- Category: Workshop Fabrication
- Hits: 17565
Fabrication Man-hours
- Fabrication man-hours are determined by the quantity of hours/tasks in each steel assembly, for example, each column, beam, brace, assembly, or bracket.
- The average constants are for high repetition portal frame and high rise type work. The ranges are for differences in piece size, detail, repetition, and fabrication methods.
- These constants are based on conventional fabrication methods used by most fabricators, ie manual gas cutting and magnetic broach drilling, and semi-automatic "mig" or "flux core" welding.
- With semi-automated saw and drill lines output is much higher but machine costs are higher, and generally the market does not differentiate costs because semi-automation affects only part of overall fabrication.
- The constants include for reading fabrication drawings, stacking and sorting materials, marking out, turning, grinding edges and welds, operator setting up, servicing gear such as welders and grinders, and QA including average rework.
- These constants are "whole of job", and hence will differ from spot check times which will not be representative of a complete job due to the tendancy not to include downtime and variances in productivity.
- Repetition affects productivity in different ways, and for some labour operations can have a significant impact on output, while other labours produce only slight improvements. A high degree of difficulty can also have a large impact on output, for example, very detailed drawings, angled assembly, low repetition of detail, complex set out.
Description | Tasks | Average | Range (Min-Max) | ||
Plates, brackets, and fly braces | |||||
Prepare plate connections, cleats and stiffeners, rectangular | piece | 4.5 min | 3-6 min | ||
shape ex flat bar, not exceeding 300mm wide or 16mm | |||||
thickness; guillotine to size and punch holes, using hydraulic | |||||
ram punch and shear machine. | |||||
Same as last but irregular shape ex plate, or exceeding | piece | 9 min | 6-30 min | ||
300mm wide or 16mm thickness; cut to size and form holes— | |||||
punch and shear, flame cut, or drill equipment. | |||||
Prepare angle brackets or fly braces not exceeding 1.5m long; | piece | 9 min | 6-12 min | ||
guillotine to length and punch holes—using punch and shear. | |||||
Slotted holes in maximum 20mm plate or angle—punched and | slot | 7.5 min | 6-10 min | ||
flame slotted. | |||||
Mark and tack plate connections, cleats and stiffeners in | No | 6.5 min | 5.5-7.5 min | ||
position on beams, columns etc, square and not exceeding | |||||
400mm length. | |||||
Same as last but bracing cleats, plates 400mm to 1000mm | No | 12 min | 8-15 min | ||
length, or hip rafter plates etc. | |||||
Cutting sections | |||||
Cut secondary sections, up to 150mm—angles, PFCs, HS | piece | 15 min | 12-20 min | ||
Extra Value for each end mitre cut, or notch cut | end | 6 min | |||
Extra Value straight join including prepare and vee butt weld | join | 1.0 hr | |||
Cut sections to length, up to 310 UB/UC/PFC/HS | piece | 28 min | 26-30 min | ||
Extra Value for each end mitre cut, or notch cut | end | 12 min | |||
Extra Value cut and form taper end, approx 300mm long | end | 45 min | |||
Extra Value straight join including prepare and vee butt weld | join | 2.5 hr | 1.5-3 hr | ||
Cut sections, over 310 UB/UC/PFC/RHS | piece | 40 min | 35-55 min | ||
Extra Value for each end mitre cut, or notch cut | end | 15 min | |||
Extra Value cut and form taper end, approx 500mm long | end | 72 min | 60-80 min | ||
Extra Value straight join including prepare and vee butt weld | join | 4.5 hr | 3.5-5.5 hr | ||
Labours to all sections | |||||
Drill bolt holes in structural sections | hole | 6.5 min | 4.5-7.5 min | ||
Form slotted bolt holes in structural sections | slot | 15 min | |||
Gas cut and grind edges for cut outs, penetrations, straight | metre | 20 min | |||
Same as last, circular | metre | 30 min | |||
Assemble and tack portal frame knee, apex, or k-brace join | join | 1.25 hr | 1-1.5 hr | ||
Assemble secondary section frame joins | join | 30 min | 20-45 min | ||
Precambering; up to 310 UB or UC | No | 2.5 hr | 1-3 hr | ||
Precambering; over 310 UB or UC | No | 3.5 hr | 3-6 hr | ||
Cut, prepare and assemble corbels, tapers, haunchings etc | No | 1 hr | 0.75-2 hr | ||
max. 1m long | |||||
Assemble composite members, e.g. crane beam channel onto | metre | 30 min | |||
UB | |||||
Truss cutting and assembly | |||||
Cut truss diagonals and struts | piece | 12 min | 10-15 min | ||
Extra Value mitre cut or notch ends | end | 7.5 min | 6-9 min | ||
Cut, prepare, join and weld chord, maximum 250 PFC or UB | chord | 1.5 hr | 1.25-2 hr | ||
x 12m long | |||||
Mark out and set up jig for truss assembly x 12m long | No | 4 hr | 3-6 hr | ||
Assemble truss top and bottom chords with diagonals and | truss | 4 hr | 3-6 hr | ||
struts x 12m long, in jig | |||||
Extra Value to precamber truss, x 12m long | No | 2 hr | 1-3 hr | ||
Diagonal bracing | |||||
Diagonal bracing rod cut, join, assemble turnbuckles, threaded | No | 40 min | 20-60 min | ||
ends | |||||
Diagonal bracing angle cut, join, drill bolted ends | No | 50 min | 30-75 min | ||
Welding—80% downhand, 20% vertical | |||||
5 and 6mm fillet weld | m | 18 min | 15-22 min | ||
8mm fillet weld—2 runs | m | 32 min | |||
10mm fillet weld—3 runs | m | 46 min | |||
12mm fillet weld—4-5 runs | m | 72 min | |||
Vee prepare end of UB, UC, PFC, HS for butt weld, max | end | 8 min | |||
300mm depth | |||||
Same as last, over 300mm | end | 12 min | |||
Vee butt weld up to 12mm | m | 90 min | |||
Vee butt weld over 12mm, up to 16mm | m | 150 min | |||
Extra Value for backing strip to joins in SHS | join | 7.5 min | |||
Extra Value for backing strip to joins in CHS | join | 30 min | |||
Hit and miss stitch 6mm fillet weld | m | 10 min | |||
Miscellaneous | |||||
H.D. bolt assembly into pairs | pairs | 6 min | |||
Unload and stack inwards steel, and load out fabricated steel | tonne | 1.5 hr | 1.25-2 hr | ||
onto trucks | |||||
Productivity factors—against the constants above | |||||
General: market, complexity or regional | 0.85-1.33 | ||||
Site fabrication and welding | 2.00-4.00 |