Engineer | Construction | Estimation of Man hours for Welding Piping. Yield of Welders

ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS. The image shows a welder in actionENGINEER | CONSTRUCTION | PIPING WORKS MAN-HOURS 


Piping Projects - Estimation man hours for welding pipe

ENGINEER | CONSTRUCTION | ESTIMATION OF MAN HOURS FOR WELDING PIPING. YIELD OF WELDERS


Calculation of inch diameter of the welding
Firstly we are going to divide the welding of pipes in two big groups
1 - Piping where only it goes away to quality control for Hydraulic Tests
2 - Piping where we make the quality control with not destructive Test (for example RT or UT) in addition to the Hydraulic Test.




At present for piping works; the Contractors make the Engineering; for example: by means of isometric drawing, pipe model that allows a fast construction in Workshop and an easy assembly at Site.
Each Isometric line is divided in Spools for its fabrication in the Workshop when finished the Spools; these are moved to its place of Work for its adjustment weld and mounting in the field. In general, with an Engineering Standard achieves that the welding during the prefabricated one (that is executed more rapidly than those of field) reach between 70 to 90 % of the whole to execute achieving by this way a minor expense of Man-hours.
We must differentiate also the Time of Welding, according to the material that we work. For the time being, we will refer to the pipes of Steel Carbon.

It is also necessary to understand that the Time of Welding will change according to the Thickness of the pipe (with more thickness, we need more time of preparation of bevels and of work of Welder because it has to refill more) and its Diameters (to major diameter, major difficulty to move them).
Finally, we will give here times Standard (where the workers, do not work for production or completed task).

For the first type of welding (where quality is controlled only with Hydraulic Test) and for a pipe of 4 inches Standard of Steel Carbon, the time for an inch of welding (the group is composed by an assistant, an official and a welder) is 0,70 MAN HOURS * inch. for welding field and 0,40 MAN HOURS *inch. for prefabricated welding. Or if they work 10 hours per day, every group, it will produce about 42 and 75 inches day, respectively. 


Look out!
to estimate the total number of man-hours per inch should be considered field support staff, the amount of personal varies with the complexity of pipe handling, example height, layout and more. (In Workshop, for a pipe of 4 inches the proposed staff is sufficient).

For the second type of welding (here quality is controlled with Not destructive Test, in addition to the Hydraulic Test) and for the same diameters the times for inch of welding in the field, will be of 2 MAN HOURS * inch. welding and 1 MAN HOURS *inch. of welding in prefabricated, the production for 10 hours of work is for every group of 15 and 30 inches per day respectively. 


Look out!
to estimate the total number of man-hours per inch should be considered field support staff, the amount of personal varies with the complexity of pipe handling, example height, layout and more. (In Workshop, for a pipe of 4 inches the proposed staff is sufficient).

Note:
The times include:
Welding of piping
They do not include:
A complication in the handling of piping, Painting - Insulation - Supports - Clamps; Scaffolding for piping.

Basic Skills of an Estimator

Basic skills

The estimator needs innate basic skills to be successful in developing his profession. Obviously, these skills are perfected with experience, but minimally the estimator must have certain innate skills to perform this task.
Anyone looking to start in the estimator career should have a combination of basic skills, such as those detailed in Figure 1.

Basic Skills of an Estimator.

Math skills.

Estimation by nature requires the formulation of many mathematical operations and complex calculations.
Proficiency in math is an essential requirement for beginners.

Communication skills.

Another skill required is the beginner's natural ability to develop good oral and written communication.
The success of the project is often hidden in the details and in its correct evaluation.
In most situations it is necessary to have fluent communication with:
Colleagues who are specialists in the type of Project being quoted.
With suppliers of equipment or services.
With the Client.
With possible subcontractors.
Or simply with the participants of the work meetings.
Good writing is another indispensable skill that will allow you to present complex reports in a clear and concise manner.

Perseverance or persistence

This trait is a hidden gem, but necessary in the personality of the estimator. The estimators must be tenacious. Perseverance is applied for example in the laborious action of looking for the best price of an endless number of materials of a project in a universe of suppliers.
The feature of persistence makes the estimator fulfill in completing all aspects of the Offer within the established deadlines regardless of the effort to be made.

Honesty and reliability.

Estimation work requires honesty and reliability.
These qualities are required by:
The shareholders of the Company who seek economic success and the prestige of their Company.
Your own colleagues who will then manage the Projects from the Estimator's preliminary analysis.

How to choose a Contractor

How to choose a Builder

How to choose a Contractor
In this audio, number 3, we discuss the main functions of the Customer's Purchasing Department and the role this Department plays in the selection of the most suitable Contractor. 

How to Estimate

How to execute Construction Works and Industrial Assemblies. Podcast N.2




How to Estimate

How to make an Estimation

In this audio, which is the second of a series of Podcasts, the tasks that an Estimator or group of Estimators usually performs to quote a Project and the most demanded skills in the search profile of a successful Estimator are broadcast.

How to execute Construction Works and Industrial Assemblies.

How to perform Industrial Building and Assembly Works.



How to execute Construction Works and Industrial Assemblies.
Podcast#1

General information

In this first Podcast, generalities are disseminated on how to estimate and execute the Construction and Industrial Assembly Works.






Valve mounting times

Estimator's Piping Man-hours Tool. Example


Here is a simple example of how to estimate the manpower consumption in the assembly of Piping. This example is taken from my book "Estimator's Piping man-hours Tool".

Description of the task.
In this case, we will estimate the consumption of man-hours to carry out a modification of an existing installation.
 
The modification consists of installing a new centrifugal pump with its suction and discharge piping between existing 6-inch manifolds.
The Mhr estimate does not include labor for the assembly of the centrifugal pump.

With respect to tie-ins, the Contractor shall only execute the insertion of the two 6 "x 4" tie-ins into the existing collectors. The shutdown of the plant, the emptying of the pipes before the execution of the anchorages, the provision of scaffolding and installations and the subsequent cleaning of the intervened area will be planned and executed by the Client's personnel.
The work in question is intended to be carried out over a long period of inactivity in the area of the plant where the work is to be carried out.

The steps to follow to estimate the hours required for this Project are:

(a). Estimation of the quantity of Mhr for the manufacture and assembly of the supports in contact with the pipes.

(b). Estimation of the amount of Mhr for the option to perform the handling, assembly, and welding of the Piping directly in the field.

(c). Same as the previous one, but running prefabricated spools and field welding on tie-ins and adjusting spools.

(d). Estimation of Mhr for cleaning and painting of supports and pipes.

The lines to be mounted are shown in Figures N°2 and N°3.


Discharge Piping of Centrifugal Pump Figura 2

e-Book "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows a discharge Piping. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS


Suction Piping of Centrifugal Pump. Figure N°3

e-Book "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the suction piping of centrifugal pump of the Example N° 2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS


List of materials in the discharged section


Pipe diameter 4” A 53 SCH 40, quantity 2,50m 
Elbow 90° RL NPS 4", ends but weld A234 Gr B Standard, quantity 2. 
Flange 4" SO S150 #, quantity 4. 
Flange NPS 21/2 "So S150 #, quantity 1. 
Gate Valve NPS 4" S150 #, quantity 1. 
Check valve NPS 4" S150 #, quantity 1. 
Reduction concentric 4"x 21/2", quantity 1. 
Pipe NPS 21/2", quantity 0.40 m. 
TEE with a reduction of 6" x 4", quantity 1.

Suction section Materials List

Eccentric reduction of 4"x 3" quantity 1. 
TEE with a reduction of 6"x 4" quantity 1. 
Flange NPS 4" type SO S150# quantity 2. 
Flange" NPS 3” SO S150 # quantity 1. 
Gate Valve NPS 4" S 150# quantity 1.
Filter NPS 4 "S 150# quantity 1. 
Elbow LR 90° NPS 4" quantity 1.
Pipe NPS 4” SCH 40quantity 1.50m.

Steps to execute the Estimation

1-Calculation of supports 

For this with the list of materials and the tables of eBook where we have the weights of the elements, we calculate the weights of the suction and discharge sections of the pump as shown in the following table.

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

2 - Calculation of the Man-hours for pre-manufacture and assembly of supports 

For this we are worth the total weight of the section calculated in the previous step that is equal to 327.09 Kg. And we divide it by the unit weight of the 4" SCH40 (16.06 Kg/m) pipe in order to find the equivalent length in NPS 4" pipe lengths for these Piping sections or Sea 327,09/16,06 = 20.44 m (equivalent length of the section in NPS 4 "pipe meters); With this data and applying the table of the eBook estimate the number of man-hours for prefabrication and mounting of supports. The information is appreciated in the lower chart, which whole is 23,91Mhr.

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the pre-manufacture and assembly of supports | Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

3 - Calculation of man-hours by sandblasting and paint of pipe and accessories

To do this we calculate first the surface to sand and paint. The length of the stretch is equal to the length of the straight pipe more the aggregation of one meter of pipe for an accessory, or equal to 23 m, since the unitary area of the pipe is equal to 0,36 m2/ml, we obtain the entire area multiplying two values or 23 x 0,36 = 8,28 m2.

To the previous value, we affect it with the yields indicated in the tables of the Manual and as we see in the bottom sheet the total of estimated hours is total, man-hours for sandblasting and painting of accessories = 12.42 + 18.22 = 30.64 Mhr.


eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the sandblasting and paint of pipes and accessories |Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

4 - Calculating man-hours by sandblasting and painting of Supports

To estimate the surface of supports to sand and paint we use the coefficient that gives us the relationship surface by weight in structures. For this case, we use the coefficient of light structures that are 35 m2/ton of support.

The total weight of the supports is obtained from the equivalent system length in NPS 4"pipe meters which are 20,44m and multiplied by the necessary kilograms of support per tube of pipe (2 Kg/m). So we have 20.44 x 2 = 40.88 Kg (round to 41kg). With this data and the yields indicated in the tables of the eBook, we operate according to the table below and give us a total of 5.33 Mhr.

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the sandblasting and painting of Supports | Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

Case II (A) man-hours assembly and welding in Situ

5 – Mhr of assembly and welding executed on the site 

Using the labor yields indicated in the tables of the eBook we obtain the man-hours required for this task.
The total Mhr is 70.58 according to the table below.

e-Book "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the Mhr of assembly and welding executed on the site | Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

The number of inches executed in piping fabricated in the site by a welder, pipefitters and an assistant (8-hour working days) is for this case of 36,80 inches per day. The value that matches what was executed in other similar works.
The value of 36.80 inches per day, arises from performing a 3 simple rule between the welded inches (in the upper table are 99") the total man-hours of the upper panel (discounting the hours of the assembly of the valves and the filter) which is 64.58 Mhr and the daily working hours of the crew which are 24 hours. The equation is:
99" x 24 hours/ 64.58 hours = 36.80 inches per day
CASE II (B) Man-hours for Assembly and Welding with Prefabricated. 
6.Mhr per Mounting and welding if working with prefabricated.
Note: For prefabrication and only in this particular case, we take a significant reduction of 50% in the Mhr consumption of the TABLES


In this example, the field welds to be executed are for tie-ins of the NPS 6" and for adjustment of spools. We have eight field welds to run four of 6" and four of 4", therefore, we have:

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the Mounting and Welding man if working with prefabricated | Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

Comparison of the total number of man-hours required per table for the 2 options with/without prefabricated.
The analysis of the two options that we follow to execute the work either with or without prefabricated is shown in the following sheet and as we see in the result when we work with prefabricated we employ 21.38 Mhr less.

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the  2 options with/without prefabricated | Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

Corrections to be applied.

A. Correction by variables or Correction by the influence of variables that affect the TABLE Estimation. For this Example, hypotheses are formulated about the degree of influence of the variables that affect this Project, so if the resulting value is different from the unit, the Table value must be adjusted by that factor. 
The variables listed are not the only ones; it is the Estimator's or Budgeter's responsibility to define them for each Budget. 
We will now analyze the variables listed. 

1. Deviations from the consumption of hours for an Assembly in standard conditions according to the experience of the Installer in the execution and supervision of similar projects. 

Has your company executed projects of this type? How often? How often? What is the experience of your supervision for this type of project? Do you have qualified and experienced staff available for this project?
Answer: This is a simple task of knowledge of the Installer; the variable is weighted at 100%. 

2. Deviations from the consumption of hours for an assembly under standard conditions according to the information available for drawing up the offer. 
Is the Quality of the Preliminary Engineering for quotation sufficient? Was a visit to OBRA made with experienced staff who reviewed all aspects that will influence the performance of staff and Construction Teams during the visit? 
Answer: This is a simple task so the variable is weighted at 100%. 

3. Deviations from the consumption of hours for an assembly under standard conditions according to the degree of labor and union requirements. 
What are the working hours, will you be working at night too? Does the project have a very demanding schedule? Evaluate the local union and consider, for example, how many people in the union's job bank should be covered by the agreement and how this affects the project's performance. 
Answer: The task is of little importance and there is not a severe degree of labor demand... The Regional Trade Union does not act for these sizes of enterprises. Therefore, the variable is weighted with 100%. 

4. Deviations from the consumption of hours for an assembly in standard conditions according to the type of soil on site and the ease of access to the site. 
What is the condition of the site? Is it low and muddy and difficult to drain, or is it high and dry? Will your staff have to travel a long way to get to work? Are the access roads passable? 
Answer: This is a covered place with a stable concrete floor and easy access. The variable is weighted at 100%.5. Qualification by the climatic conditions where the work will be executed. 

5. Deviations from the consumption of hours for an assembly under standard conditions according to climatic factors. 
What is the historical climatic condition in the Project area? If necessary, can they be checked? What are future weather forecasts? Will there be much rain, wind or snow? What differences are expected in the climate with respect to the place where your people usually work? 
Answer: The workplace is ideal because it is an enclosed area and there is no loss of performance due to climatic factors. The weighting of the variable of 100%. 

6. Deviations from the consumption of hours for an assembly under standard conditions due to the level of height at which the work is carried out. 
In this case, the tasks are executed at a normal level of height so it applies the Standard Table value. The weighting of the variable is 100%. 

Conclusion: After analyzing these 6 variables, no deviations are detected with respect to the consumption of hours for an assembly under standard conditions. The hour's consumption obtained from the Tables for this Example is not changed.

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

B. Correction by Location.

Understands the correction to be made in the Man-hours of a table, depending on whether to execute work within a plant in operation or to build a new work in an isolated site. When the work is carried out within a plant in operation, the importance of the correction is linked to the characteristics of the plant in operation.
For this project because splices must be made in the suction and discharge manifolds we will charge 10% more hours to execute the work; It is understood that the people of plant operation delivers the collectors ready for their intervention, the final the estimate would be.

eBook "Estimator's Piping Man-hours Tool: Estimating Man-hours for a Project - Manual of Man-hours, Examples (Process Piping Book 1)". the image shows the chart of calculation of the Correction by Location | Example N°2 of the eBook. ENGINEER | CONSTRUCTION | PIPING WORKS MAN HOURS

C. Correction by Materials.

TABLE times apply to steel pipes ASTM A53 Gr A / B, EWR A-53 / API 5L PSL2 Gr B.
When the materials of our work are different, a conversion factor must be applied for material change that we call k (Specific issue that we discussed in the Manuals No. 2 to 8). For this case, the elements of the section are of similar quality to the one used to calculate the yields of TABLES, so the conversion factor k is 1 and the total hours are not modified.

Estimator's Piping Man-hours Tool. Example

Estimator's Piping Man-hours Tool. Example

Here is a simple example of how to estimate the manpower consumption in the assembly of Piping. This example is taken from my book "Estimator's Piping man-hours Tool".

Description of the task.
In this case, we will estimate the consumption of man-hours to carry out a modification of an existing installation.
The modification consists of installing a new centrifugal pump with its suction and discharge piping between existing 6-inch manifolds. The Mhr estimate does not include labor for the assembly of the centrifugal pump.
With respect to tie-ins, the Contractor shall only execute the insertion of the two 6 "x 4" tie-ins into the existing collectors. The shutdown of the plant, the emptying of the pipes before the execution of the anchorages, the provision of scaffolding and installations and the subsequent cleaning of the intervened area will be planned and executed by the Client's personnel. The work in question is intended to be carried out over a long period of inactivity in the area of the plant where the work is to be carried out.

The steps to follow to estimate the hours required for this Project are:

(a). Estimation of the quantity of Mhr for the manufacture and assembly of the supports in contact with the pipes.

(b). Estimation of the amount of Mhr for the option to perform the handling, assembly, and welding of the Piping directly in the field.

(c). Same as the previous one, but running prefabricated spools and field welding on tie-ins and adjusting spools.

(d). Estimation of Mhr for cleaning and painting of supports and pipes.

The lines to be mounted are shown in Figures N°2 and N°3.

Discharge Piping of Centrifugal Pump Figura 2



Suction Piping of Centrifugal Pump. Figure N°3



List of materials in the discharged section

Pipe diameter 4” A 53 SCH 40, quantity 2,50m
Elbow 90° RL NPS 4", ends but weld A234 Gr B Standard, quantity 2
Flange 4" SO S150 #, quantity 4
Flange NPS 21/2 "So S150 #, quantity 1
Gate Valve NPS 4" S150 #, quantity 1
Check valve NPS 4" S150 #, quantity 1
Reduction concentric 4"x 21/2", quantity 1
Pipe NPS 21/2", quantity 0.40 m
TEE with reduction of 6" x 4", quantity 1

Suction section Materials List
Eccentric reduction of 4"x 3" quantity 1
TEE with reduction of 6"x 4" quantity 1
Flange NPS 4" type SO S150# quantity 2
Flange" NPS 3” SO S150 # quantity 1
Gate Valve NPS 4" S 150# quantity 1
Filter NPS 4 "S 150# quantity 1
Elbow LR 90° NPS 4" quantity 1
Pipe NPS 4” SCH 40quantity 1.50m

Steps to execute the Estimation

1-Calculation of supports

For this with the list of materials and the tables of eBook where we have the weights of the elements, we calculate the weights of the suction and discharge sections of the pump as shown in the following table.



2 - Calculation of the Man-hours for pre-manufacture and assembly of supports. 
For this, we are worth the total weight of the section calculated in the previous step that is equal to 327.09 Kg. And we divide it by the unit weight of the 4" SCH40 (16.06 Kg/m) pipe in order to find the equivalent length in NPS 4" pipe lengths for these Piping sections or Sea 327,09/16,06 = 20.44 m (equivalent length of the section in NPS 4 "pipe meters); With this data and applying the table of the eBook estimate the number of man-hours for prefabrication and mounting of supports. The information is appreciated in the lower chart, which whole is 23,91Mhr.



3 - Calculation of man-hours by sandblasting and paint of pipe and accessories.
To do this we calculate first the surface to sand and paint. The length of the stretch is equal to the length of the straight pipe more the aggregation of one meter of pipe for an accessory, or equal to 23 m, since the unitary area of the pipe is equal to 0,36 m2/ml, we obtain the entire area multiplying two values or 23 x 0,36 = 8,28 m2.
To the previous value, we affect it with the yields indicated in the tables of the Manual and as we see in the bottom sheet the total of estimated hours is total, man-hours for sandblasting and painting of accessories = 12.42 + 18.22 = 30.64 Mhr.



4 - Calculating man-hours by sandblasting and painting of Supports.
To estimate the surface of supports to sand and paint we use the coefficient that gives us the relationship surface by weight in structures. For this case, we use the coefficient of light structures that are 35 m2/ton of support.
The total weight of the supports is obtained from the equivalent system length in NPS 4" pipe meters which is 20,44m and multiplied by the necessary kilograms of support per tube of pipe (2 Kg/m). So we have 20.44 x 2 = 40.88 Kg (round to 41kg). With this data and the yields indicated in the tables of the eBook, we operate according to the table below and give us a total of 5.33 Mhr.


Case II (A) man-hours assembly and welding in Situ

5 – Mhr of assembly and welding executed on the site
Using the labor yields indicated in the tables of the eBook we obtain the man-hours required for this task.
The total Mhr is 70.58 according to the table below.



The number of inches executed in piping fabricated in the site by a welder, pipefitters and an assistant (8-hour working days) is for this case of 36,80 inches per day. The value that matches what was executed in other similar works.

The value of 36.80 inches per day, arises from performing a 3 simple rule between the welded inches (in the upper table are 99") the total man-hours of the upper panel (discounting the hours of the assembly of the valves and the filter) which is 64.58 Mhr and the daily working hours of the crew which are 24 hours. The equation is:
99" x 24 hours/ 64.58 hours = 36.80 inches per day


CASE II (B) Man-hours for Assembly and Welding with Prefabricated. 

6. Mhr per Mounting and welding if working with prefabricated.

Note: For prefabrication and only in this particular case, we take a significant reduction of 50% in the Mhr consumption of the TABLES.
In this example, the field welds to be executed are for tie-ins of the NPS 6" and for adjustment of spools. We have eight field welds to run four of 6" and four of 4", therefore, we have:



Comparison of the total number of man-hours required per table for the 2 options with/without prefabricated.
The analysis of the two options that we follow to execute the work either with or without prefabricated is shown in the following sheet and as we see in the result when we work with prefabricated we employ 21.38 Mhr less.



Corrections to be applied.


A. Correction by variables or Correction by the influence of variables that affect the TABLE Estimation. For this Example, hypotheses are formulated about the degree of influence of the variables that affect this Project, so if the resulting value is different from the unit, the Table value must be adjusted by that factor.
The variables listed are not the only ones; it is the Estimator's or Budgeter's responsibility to define them for each Budget.
We will now analyze the variables listed.

1. Deviations from the consumption of hours for an Assembly in standard conditions according to the experience of the Installer in the execution and supervision of similar projects.
Has your company executed projects of this type? How often? How often? What is the experience of your supervision for this type of project? Do you have qualified and experienced staff available for this project?
Answer: This is a simple task of knowledge of the Installer; the variable is weighted at 100%.

2. Deviations from the consumption of hours for an assembly under standard conditions according to the information available for drawing up the offer.
Is the Quality of the Preliminary Engineering for quotation sufficient? Was a visit to OBRA made with experienced staff who reviewed all aspects that will influence the performance of staff and Construction Teams during the visit?
Answer: This is a simple task so the variable is weighted at 100%.

3. Deviations from the consumption of hours for an assembly under standard conditions according to the degree of labor and union requirements.
What are the working hours, will you be working at night too? Does the project have a very demanding schedule? Evaluate the local union and consider, for example, how many people in the union's job bank should be covered by the agreement and how this affects the project's performance.
Answer: The task is of little importance and there is not a severe degree of labor demand... The Regional Trade Union does not act for these sizes of enterprises. Therefore, the variable is weighted with 100%.

4. Deviations from the consumption of hours for an assembly in standard conditions according to the type of soil on site and the ease of access to the site.
What is the condition of the site? Is it low and muddy and difficult to drain, or is it high and dry? Will your staff have to travel a long way to get to work? Are the access roads passable?
Answer: This is a covered place with a stable concrete floor and easy access. The variable is weighted at 100%.5. Qualification by the climatic conditions where the work will be executed.

5. Deviations from the consumption of hours for an assembly under standard conditions according to climatic factors.
What is the historical climatic condition in the Project area? If necessary, can they be checked? What are future weather forecasts? Will there be much rain, wind or snow? What differences are expected in the climate with respect to the place where your people usually work?
Answer: The workplace is ideal because it is an enclosed area and there is no loss of performance due to climatic factors. The weighting of the variable of 100%.

6. Deviations from the consumption of hours for an assembly under standard conditions due to the level of height at which the work is carried out.
In this case, the tasks are executed at a normal level of height so it applies the Standard Table value. The weighting of the variable is 100%.

Conclusion: After analyzing these 6 variables, no deviations are detected with respect to the consumption of hours for an assembly under standard conditions. The hour's consumption obtained from the Tables for this Example is not changed.



B. Correction by Location. 

Understands the correction to be made in the Man-hours of the table, depending on whether to execute work within a plant in operation or to build a new work in an isolated site. When the work is carried out within a plant in operation, the importance of the correction is linked to the characteristics of the plant in operation.

For this project because splices must be made in the suction and discharge manifolds we will charge 10% more hours to execute the work; It is understood that the people of plant operation deliver the collectors ready for their intervention, the final estimate would be.



C. Correction by Materials.
TABLE times apply to steel pipes ASTM A53 Gr A / B, EWR A-53 / API 5L PSL2 Gr B.
When the materials of our work are different, a conversion factor must be applied for material change that we call k (Specific issue that we discussed in the Manuals No. 2 to 8). For this case, the elements of the section are of similar quality to the one used to calculate the yields of TABLES, so the conversion factor k is 1 and the total hours are not modified.