Building construction projects are simple only until sub-contractors get into the picture and things start getting clumsy. Responsibilities are dispersed, the construction company never achieves the designated results on time, contractors are nowhere to be found and metal fabricators are blamed.
Despite these blame games, we see buildings being constructed. Most buildings stand tall with accurately fitted fabricated metal and/or wooden building products. But at the backend, there are delays that no one knows of and metal fabricators suffer. Why is it so? And are the metal fabricators really to be answerable during such ordeals?
To answer these questions let us walkthrough a typical scenario of a bespoke building products fabrication contract. Evaluating the roles of building product CAD engineers, fabricators, metal contractor and the construction company, analysis of each situation can certantly hold some answers.
Start with the bid for contracting building product fabrication
Let's call the metal fabrication company Gamma. Associated with the metal contractor, Beta will bid for the contract for a construction company, called Alpha. Building product designers, contractors and engineers at Beta will prepare the necessary technical documents, bill of materials, and cost estimates. Beta’s team will also get busy in developing submittal drawings, transmittal documents and tentative schedules along with the bid.
Now, given that Beta’s bid was the most economical compared to other metal contractors that bid; they won the tender for Alpha’s iconic building construction project. Beta now will have to commit to near approximate delivery schedules, milestones and other delivery dates by estimating the scope of work.
The middle stage: To do or not to do
A project like this all begins with the development of 2D fabrication shop drawings; steel shop drawings and are summarized into 3D models to coordinate with Alpha and Gamma. The designer ideally communicates back with the architects at Alpha to develop appropriate geometry of the staircase, handrail, design the railings, etc., and develop the fabrication drawings, assembly and installation drawings. Multiple RFIs will be generated. Several copies of the drawings will be sent across to both Alpha and Gamma to evaluate the designs and fabrication competence.
Evaluating CAD design engineer’s situation
Now, ideally, it takes a week’s time to prepare fabrication drawings for steel stairs in standard CAD software like AutoCAD. However, based on the time taken to revert on RFIs, engineering detailing, customization, and volume of the work, this time may increase or decrease. The engineers and architects at Alpha and fabricators at Gamma’s shop floor will develop mark-up drawings and the final models are then updated by the CAD engineers. This might again add a week or two.
Evaluating building product fabricator’s situation
With the wide adoption of CAD and its APIs, direct DXF files for machining can be developed and can generate NC codes to operate CNC machines directly from the models and DWG files. Despite the automation, the release of fabrication drawings for shop floor takes several weeks, give or take.
Once the shop drawings are approved from both ends and finally released to the machine shop, raw materials are ordered. Internal BOMs are generated and the fabrication begins. Their delivery dates are based on the machining time, idle or down time of machines, waiting in queue time for the job and other processes on shop floor.
Bump: What really matters for the staircase?
Now, as a reputed metal contracting firm, Beta will ensure that their deliverables are not only sturdy with appropriate technicalities but also fit the architect’s and structural engineer’s design. That’s what makes them sellable to the construction company, Alpha. Hence, apart from 2D shop drawings for CAD engineers, what really matters for a steel staircase model or design is surface finish, look and feel geometry and overall features of the staircase.
Beta CAD engineer will focus on setting the stringers, tread, height, railing, balustrades, shape (spiral or straight), and everything as per the client’s need. They consider the market needs, does research for designs as per the application, building type – residential, commercial or industrial staircases – and develop the models accordingly.
One important factor that is considered while designing or modeling a building product like staircase is ergonomics. Its use is frequent, rough and harsh; and hence the ergonomics and aesthetics are paid the highest attention. The user shouldn’t face difficulties in ascending or descending and so the height of the riser is identical across the building and usually set the maximum at 7.75 inches high.
But ideally, Beta engineers will coordinate with the Alpha engineers to know the building type and location to adhere to region-specific standards - ASME, ANSI, BS, etc. When the staircases are inside the building envelops, headroom is a factor that decides the stair height to avoid hitting the head and eliminate safety risks with a clearance of 6 ft. 8 inches – standard value.
The end: Are fabricators really to be blamed?
Now, once the Beta CAD engineers are done developing the final models of staircases and fabrication drawings are released to Gamma’s fabrication facility. With a process as portrayed in this simplest story, two intermediate levels of promised delivery schedules and numerous subjects that cause delays, one cannot really blame the fabricators only.
So when Gamma, the fabricator, fails to deliver the fabricated steel staircase to Beta on time, which in turn will cause the delay for Alpha, the foremen to install them on site, there could be multiple reasons. Some of which are enlisted:
- The architects and engineers at Alpha caused the delay in reverting the RFI raised by Beta CAD engineers
- Beta Fabricators raised change orders in CAD drawings due to their incapacitated tooling facility
- Raw materials were not transmitted to the fabrication facility on time due to unavoidable factors
- Beta CAD engineers overlooked certain obvious factors, like DFM, which caused the ECOs from the shop floor
- The end client of Alpha (construction company) asked for drawing revision at the last moment
- The building design changed from the stakeholders’ end which caused the staircase designs to change
- Price conflicts arise between either of the three Alpha, Beta or Gamma
Instead, you should focus on including the fabricator early into your designing stage and the sub-contractor should ensure that this happens to align the bespoke design preferences and profitability.