How to Estimate Input and Consumption Materials.
In this step, the Estimator must analyze what the Input and Consumption Materials are, and how much they cost.
The term consumables, or consumption materials, refers to all the auxiliary material used to carry out work, but which is not incorporated into the construction…
On the other hand, the contribution or input material is also an auxiliary material, but it is incorporated into the construction.
This step of the estimation includes all indirect materials used during the execution of work.
Consumable materials are auxiliary materials used during the construction and assembly process of a project, but as their name suggests, they are consumed and not detected in the finished project.
Examples of consumable materials:
Consumption materials in civil works
Some civil works estimators add the following costs to the consumable item:
-Waste of form-work material, produced by cutting, reusing, and handling.
-The use of elements for the assembly and fastening of the form works such as nails, threaded rods, spacers, staples, etc.
Caution: The form-work has a significant value within the cost of m3 of concrete, and their acquisition and assembly cost is charged as a direct cost.
-For example, drills, cutters, saw blades, steel reamers, cut-off and roughing disc’s, etc.
Consumer materials in electromechanical works
-Oxidizing gases, such as acetylene and oxygen, used in oxy-cut.
-Shielding gases, such as carbon dioxide, used in the process of short-circuiting and globular transfer welding.
-Traditional binary mixture of argon and carbon dioxide, used in the MIG/MAG process, and gas-shielded tubular electrode welding.
-Special gas mixes. To be used as a protective atmosphere in MIG, TIG, and plasma cutting welds.
-We use Carbon dioxide and nitrogen as a protective or insulating inert atmosphere, etc.
How to Estimate Input and Consumption Materials – Input Materials
Input materials include any indirect material that is incorporated in whole or in part into the finished project.
Examples of input materials.
In civil works
-The wire to bind the armor.
-The spacers between the form-work wall and the reinforcement iron.
-Building additives, etc.
In electromechanical works.
-Electrical connectors and terminals, insulating tape, minor screws, adhesives, etc.
-Soldering and brazing filler metals.
-Filler materials for electric arc welding.
Attention: When working with a significant amount of inches of solder or with alloyed or special steels, the cost of these materials is important.
Some filler materials and consumption are paid for as a percentage associated with the volume of what is built and others of higher unit costs such as electrodes by their quantity and quality.
A table showing the weight of metal deposited for different joints per linear meter.
Table to calculate the amount of inputs needed in each welding process to deposit 100 kg of metal.
See next post on how to calculate indirect labor hours.
How to Estimate Input and Consumption Materials – Calculate Man Hours