Cost Engineer "Pricing Control" focuses on the examination points: construction and security engineering labor, materials

Lecture 5 Quota Consumption of Labor, Materials and Machinery Bench Shifts in Construction and Security Engineering

　　First, the construction process decomposition and working hours research

　　(1) The construction process and its classification

　　1. The meaning of the construction process

　　The construction process is the production process carried out within the scope of the construction site.

　　The construction process of building installation, like other material production processes, also includes the three elements of productivity, namely laborers (people), labor objects (materials), and labor tools (machines).

2. Classification of construction process

　　(1) According to the complexity of the construction process organization, it can be decomposed into processes, work processes and comprehensive work processes.

Process	It is organizationally inseparable and technically belongs to the same kind of construction process in the operation process	Workers, work places, labor objects, and labor tools are unchanged; they are the basic construction process and the main research objects for the preparation of construction quotas
Work process	A combination of processes that are technically and organically linked in technical operations by the same worker or the same group	Staffing, duty stations remain the same, materials and tools can be changed
Integrated work	It is carried out simultaneously in different spaces, organically linked in organization, and ultimately the sum of the construction process of a product can be obtained

　　(2) According to the characteristics of the process, the construction process can be divided into two categories: circular construction process and non-circular construction process.

　　3. Influencing factors of the construction process

　　(1) Technical factors.

　　(2) Organizational factors. Skill level of workers

　　(3) Natural factors.

　　(2) Classification of working hours

　　The main purpose of studying the working hours in construction is to determine the time quota and output quota of construction (reciprocal to each other). The study of the consumption of working hours can be divided into the consumption of workers' working hours and the consumption of working hours of the machines used by workers.

　　1. Classification of workers' consumption during working hours

Workers' working hours	Have to deplete time	Effective working hours	Basic working hours	Proportional to the amount of work
Auxiliary working hours	Proportional to the amount of work
Prepare and end working hours	It has nothing to do with the amount of work, it has to do with the content of the work
Break time
Unavoidable interruptions
loss Time	Redundant and fortuitous time	Excess work is caused by errors and is not included in the quota; occasional work can obtain a certain product, which is properly considered when formulating the quota
Downtime	Downtime caused by construction itself	Excludes from the quota
Downtime caused by non-construction itself	Reasonable consideration in the quota
Violation of labor discipline loses time

　　Exercise: Among the following construction work time classification options, there are () that belong to the effective working hours of workers.

　　A. Basic working hours

　　B. Break time

　　C. Auxiliary working hours

　　D. Preparation and closing of working hours

　　E. Unavoidable interruption time

　　Answer: ACD

　　2. Classification of machine working time consumption

Machine working hours	Time that must be consumed	Effective working hours	Under normal load
Reduce the load on a case-by-case basis
Unavoidable no-load working hours
Unavoidable interruption times	It is related to the characteristics of the process
Machine-related
Workers' rest time
Lost time	Excess working hours
Downtime	Downtime caused by construction itself
Downtime caused by non-construction itself
Violation of labor discipline time
Working time under low load

　　(3) Timing observation method

　　1. Classification of timing observation methods

Chronograph observation method	Time measurement method	The timing method is mainly suitable for measuring the man-hour consumption of the periodic repetitive cycle work, and is a timing observation method with high accuracy. The time measurement method only determines the working time consumption of the circulating components during the construction process, and does not study the rest, preparation and end of the workers, that is, other non-cyclical working hours. The more scientific method of determining the number of observations should be based on the combination of error theory and empirical data. The number of observations required is related to the accuracy of the required arithmetic mean and the stability coefficient of the sequence.
Realistic recording	Realistic recording is a method of studying the consumption of working hours of various natures. These include basic working hours, ancillary working hours, unavoidable interruption times, preparation and end times, and various lost times. In this way, all the information necessary to analyse working time consumption and establish quotas is available. The object of observation of the realistic recording method can be either a worker or a group of workers.
Working day realism	The working day realism method is a method of studying the consumption of various working hours in the entire work class. There are two main purposes for the use of the working day realism method, one is to obtain the basic information for the preparation of quotas. In this case, it is usually necessary to measure 3 to 4 times; the second is to check the implementation of the quota, find out the shortcomings, and improve the work. In this case, it is usually necessary to assay 1 to 3 times. Advantages: The technology is simple, the effort is not much, the application is widespread and the data is comprehensive, and it is a widely used method of compiling quotas in the mainland. Disadvantages: Due to the presence of observers, even if full preparation is made before observation, it is still inevitable that there is a certain degree of falsehood in the use of working hours; the observation workload of the working day realism method is larger, the time is more time-consuming, and the cost is also high.

　　(1) Time measurement method

Time measurement method	When selecting the method test	Interval selection of non-tightly connected components (processes or operations) during the construction process to determine man-hours with an accuracy of 0.5s. When the duration of each process or operation measured is short, the selection method is more convenient and simple at this time.
When testing by continuous method	Continuous determination of the duration of each process or operation in a construction process. It is more accurate and perfect than the selection method, but the observation technique is also more complex.

　　(2) Realistic recording method

Realistic recording	Realistic records of numeral representations	With high accuracy of up to 5s, it is suitable for construction processes with fewer components and more stable. The numerical indication method can reflect the entire working day of the worker or machine.
Graphical realistic records	The accuracy is up to 30s, the recording is simple, the time is clear at a glance, and the original record is easy to organize.
Mixed method realistic recording	Drawing on the advantages of both methods, it is suitable for collective realistic recording of working hours of more than 3 people.

　　Exercise: In the following description of the characteristics of the time measurement method, the correct one is ().

　　A. The timing measurement method is suitable for measuring repeated cyclic working time and also for determining non-cyclic working time

　　B. The timing method is more accurate and perfect than the continuous measurement method, but the observation technology is also more technical

　　C. When the duration of each process measured is shorter, the continuous measurement method is more convenient than the selection of the time measurement method

　　D. The number of observations of the time measurement method should be determined according to the method of combining error theory and empirical data

　　Answer: D

Second, the basic method of determining the consumption of manual quotas

　　(1) Determine the process operation time

　　1. Draw up basic working hours

　　The consumption of basic working hours should generally be determined on the basis of timing observation data. The practice is to first determine the man-hour consumption of each component of the work process, and then synthesize the man-hour consumption of the work process. If the product unit of measurement of the component part does not match the product unit of measurement of the work process, it is necessary to first find the conversion coefficient of the different unit of measurement, convert the product unit of measurement, and then add up to find the working hour consumption of the work process.

　　The unit of measurement of the brick wall grout is square meters, but if the grout is treated as an integral part of the construction process of the brick wall, the grout time is calculated according to the thickness of the masonry wall according to the volume of the masonry, and the grout time required for each square meter of the wall is 10min, and the grout time required for each cubic meter of masonry for a brick-thick brick wall is tried.

　　2. Formulate auxiliary working hours

　　Co-working hours can be calculated directly using the percentage of ancillary working hours specified in the work specification.

　　(2) Determine the specification time

　　The specification time content includes preparation and end time outside the operation time, unavoidable interruption time, and rest time.

　　(3) The time for drawing up the quota

　　Operation time = basic working time + auxiliary working time

　　= Basic working time / (1 - auxiliary time%)

　　Specification time = preparation and end working time + unavoidable interruption time + rest time

　　Quota time = process operation time + specification time

　　= Process operation time / (1 - specification time%)

　　Exercise: Through timing observation, the basic working hours for completing a project are 6h/m2, and the auxiliary working time is 8% of the process operation time. The specification time accounts for 15% of the working time, and the time limit for the completion of the project is () working days/m2.

　　A.0.93

　　B.0.94

　　C.0.95

　　D.0.96

　　Answer: D

　　【Exercise】If the basic working hours for completing the 1m3 wall masonry work are 0.5 working days, the auxiliary working time accounts for 4% of the process operation time. Preparation and closing of working hours, unavoidable interruptions, and rest periods account for 6%, 3% and 12% of working hours respectively, and the project time quota is () working days/m3.

　　A.0.581

　　B.0.608

　　C.0.629

　　D.0.659

　　Answer: D

　　Third, the basic method of determining the consumption of material quotas

　　(1) Classification of materials

　　1. Divide according to the nature of material consumption

Divided according to the nature of the material consumption	Materials that must be consumed	Basic data for determining material consumption quotas
Loss of material
Divided according to the relationship between material consumption and engineering entities	Solid material
Non-solid material	Turnover materials: formwork, scaffolding

　　(2) The basic method of determining the consumption of materials

Field technical measurement method	Determine the various material consumption quotas and determine the amount of material loss
Laboratory test method	Used to prepare a quota for net material usage
Field statistics method	Since it is not possible to distinguish the nature of material consumption, it can only be used as an auxiliary method for the preparation of quotas
Theoretical calculations	Use mathematical formulas to calculate material consumption quotas

　　1) Calculation of standard brick usage.

　　For example, the number of bricks per cubic meter of brick wall and the amount of masonry mortar can be calculated by the following theoretical calculation formula to calculate the respective net consumption:

　　Number of bricks used:

　　A = wall thickness× (brick length + gray seam) × (brick thickness + gray seam) (1) × k

　　where k is the number of bricks with a wall thickness×2

　　Mortar dosage:

　　B=1 - The number of bricks × brick volume

　　Loss rate = Loss amount / net consumption

　　Total loss = net consumption + loss amount = net consumption × (1 + loss rate)

　　2) Calculation of the amount of material used in the block surface layer

　　The formula for the quantity of block material per 100m2 surface layer, the amount of ash seam and the amount of binding layer material is as follows:

　　Net amount of 100m2 block material = (block length + ash seam width) × (block width + ash seam width) (100) (block)

　　100m2 net amount of ash seam material = 100-[(block length× block width× 100m2 net amount of material)] × ash seam depth

　　The amount of binding layer material = 100m2 × the thickness of the binding layer

　　Exercise: On the basis of measuring and observing the material consumption process, the method of determining the quota of various material consumption by completing the calculation of the number of products and the amount of material consumption is ().

　　A. Laboratory experiment method

　　B. On-site technical measurement method

　　C. Field statistics method

　　D. Theoretical calculation method

　　Answer: B

Fourth, the basic method of determining the quota consumption of the mechanical bench class

　　(a) determine the normal productivity of the machine for 1h pure working

　　(1) Cyclic action machinery

　　The normal continuation time of a mechanical primary cycle = the sum of the normal continuation times of each component of the cycle - the overlap time

　　Mechanical pure working 1h cycle number = 3600s / normal continuation time of a cycle

　　Mechanical pure work 1h normal productivity = mechanical pure working 1h normal cycle times× the number of products produced in one cycle

　　(2) Continuous action machinery

　　(2) Determine the normal utilization coefficient of construction machinery

　　Normal utilization coefficient of machinery = duration time of one work shift (8h) (pure working time of machinery in one work shift)

　　(3) Calculate the quota of construction machinery bench shifts

　　【Exercise】A mortar mixer with a discharge capacity of 750L, in each cycle work, the time required for transportation, loading, mixing, unloading and interruption is 150s, 40s, 250s, 50s, 40s, respectively, the overlap time of transportation and other times is 50s, and the mechanical utilization coefficient is 0.8. The output of the machine is fixed at ()m3/shift.

　　A.29.79

　　B.32.6

　　C.36.00

　　D.39.27

　　Answer: C