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

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