How to calculate the total area of the warehouse. How to plan storage areas
The material values credited by the accounting department must be stored somewhere until they are needed for the production of products. The place of storage is called warehouse. Warehouses can be various shapes and build from different materials, occupy a different area (volume). The size of the warehouse determines, on the one hand, the possibility of accommodating incoming material resources, on the other hand, the costs of its construction, depreciation (or rent) and maintenance.
The total area of the warehouse is conditionally divided into four parts:
1) usable area directly occupied by stored material resources;
2) the acceptance area, on which the acceptance and release areas are located;
3) office space for warehouse management services;
4) auxiliary area occupied by driveways and walkways.
Usable area of the warehouse determined in two ways. The first way - load calculation per 1 m 2 floor area(/floor) -
This uses the formula
where Ztot is the total amount of the stock of a material resource;
σ is the load per 1 m 2 of the floor area, and the value of σ has different values depending on the purpose of the warehouse and the type of stored inventories (Table 9.1).
Table 9.1
The value of the quantity a for various warehouses
The second way is to use the volume fill factor (q about). The capacity of any equipment for storing materials (cells, racks) is determined by the formula
where V about is the geometric volume of the corresponding equipment;
γ –specific gravity material resource;
β is the filling factor of the volume (packing density).
Knowing the amount of inventory to be stored (3 total). you can determine the required amount of equipment (cells, racks, etc.) (n) by the formula
Then the usable area of the warehouse (/floor) is calculated using the formula
where d is the length of the corresponding equipment for storing material resources;
w is the width of the equipment.
The area for acceptance and release areas (f pr) is calculated by the formula
where Q p oc is the annual flow of material resources;
k-coefficient of uneven receipt of a material resource at the warehouse (varies from 1.2 to 1.5);
t- the number of days the material resource is at the acceptance site;
σ 1, - load per 1 m 2 of area (0.25 is taken from the average load per 1 m 2 of usable area for the warehouse).
The next calculation is service area of the warehouse. It is determined by the number of employees. With a warehouse staff of up to three employees, the area of office premises is assumed to be 5 m 2 for each person; with a staff of three - five people - 4 m 2 each; with a staff of more than five people - 3.25 m 2 each.
After that, the auxiliary area is calculated. It is formed by driveways for hoisting vehicles and passages for workers. The placement of driveways and aisles is outlined in the figure with the warehouse layout. Aisle width (W) for two vehicles is determined by the formula
where B is the width of the vehicle;
C is the width of the gaps between vehicles and between them and the racks on both sides of the passage.
By setting the length of passages and passages and their width, you can calculate the total auxiliary area.
The sum of the four components will give the total area of the warehouse for storing material resources.
Cargo storage equipment can be subdivided according to the type of stored materials: for the storage of piece large-sized, container-piece, bulk, liquid and gaseous goods in accordance with the physical state and characteristics of the goods.
piece cargo can be stored in warehouses in stacks (in flat, rack or box pallets) or on racks, the types and parameters of which depend on the stored cargo, as well as the purpose of the warehouse, cargo processing technology, shelf life and other factors.
Bulk cargo stored in open storage areas in stacks and trenches of various shapes and closed warehouses, and in case of small stocks - in bunkers of various shapes.
Liquid cargo can be stored in warehouses in containers (barrels, bottles, drums) and in bulk in tanks.
For the placement of material resources, it is important to determine the total area of the warehouse and the number of equipment for storing materials.
The total warehouse area includes:
– usable warehouse area, those. the area directly occupied by the stored material (racks, stacks), f floor;
– square, occupied by acceptance and release areas, f pr,
– service area of the warehouse, occupied by office and other office space, f sl
– ancillary warehouse area, occupied by driveways and aisles f aux
The total area will be:
8.9.1 Determining the usable area
The useful area of warehouses storing metals, hardware, tools, spare parts and other products is determined in two ways: by the method of load per 1 m2 of floor area and by the method of volume fill factor.
Way load per 1 m 2 floor area is the most convenient and simple. The calculation formula looks like:
where V about- geometric volume of the corresponding equipment, m 3;
γ - specific gravity of the material or product, t / m 3;
β - coefficient of volume filling (packing density).
Knowing the amount of material to be stored, the required amount of equipment (cells, racks, stacks) P determined by the formula:
where l- length of the relevant storage equipment, m;
b- width, m.
Thus, calculating the usable storage area certain types or groups of materials and products and summing it up, we get the total usable area of the warehouse.
8.9.2. Determination of the area occupied by acceptance and release sites
In warehouses with a large amount of work, acceptance and release areas are arranged separately, and with a small amount of work - together. Required area of the receiving area:
| (8.6) |
where is the annual receipt of material, t;
σ1 - load per 1 m 2 area, t; taken approximately 0.25 of a (average load per 1 m 2 of usable area in the warehouse), t / m;
k- coefficient of uneven receipt of material to the warehouse (1.2-1.5);
t- the number of days the material is at the acceptance site (up to 2 days). The size of the release area is determined in a similar way.
8.9.3. Definition of service area
The area of the warehouse office is calculated depending on the number of employees.
With a warehouse staff of up to three employees, the office area is taken at 5 m 2 for each person; from 3 to 5 - 4 m 2 , with a staff of more than 5 employees - 3.25 m 2 per person.
8.9.4. Auxiliary area definition
The dimensions of aisles and driveways in warehouses are determined depending on the size of the stored materials, the size of cargo turnover, lifting and transport vehicles. For this purpose, use the formula:
| A=2B + 3C, | (8.7) |
where BUT- passage width, cm;
AT- width of the vehicle;
With- the width of the gaps between vehicles and between them and racks on both sides of the passage (assumed 15-20 cm).
AT absolute values the width of the main passages (passages) is taken from 1.5 to 4.5 m. The width of the side passages (passages) is from 0.7 to 1.5 m.
The height of warehouses from floor level to the tightening of trusses or rafters is usually taken from 3.5 to 5.5 m. In cases where the warehouse is equipped with an overhead crane, its height is calculated and can reach 8 m.
With approximate calculations, the total area of warehouses ^ 0 wsh can be determined depending on the usable area / floor through the utilization factor a according to the formula:
| , | (8.8) |
Warehouse is a special room for storing stocks and materials.
Methodology for calculating the total area of a warehouse.
All warehouse space consists of two parts: areas used and unused for storage. When planning, it should be borne in mind that the most rational is the ratio of these areas, equal to 2:1.
The total warehouse area can be calculated using the formula:
S common =S gr +S vsp +S etc +S km +S r.m +S p.e +S o.e. ,
Consider the procedure for calculating the quantities included in the formula.
1. Determination of the cargo area:
Sgr \u003d Q * Z * Kn / 254 * Cv * Kigo * N,
where: Q - forecast of annual turnover, rub./year; Z - forecast of the value of commodity stocks (average stock), days of turnover; Kn - coefficient of uneven loading of the warehouse; Kigo - utilization factor of the cargo volume of the warehouse; Cv - average cost of one cubic meter of goods stored in a warehouse, rub./m3; H - height of stowage of goods for storage, m; 254 is the number of working days in a year.
Kn \u003d Gmax / Gsr,
Gmax - maximum cargo turnover; Gsr - medium cargo turnover.
Kigo \u003d Vpol / Sob * H,
where: Vfull is the volume of goods in the package, which can be stacked on this equipment along its entire height, m3; Sb - the area occupied by the projection of the external contours of the supporting equipment on a horizontal plane, m2; H- cargo stacking height, m.
2. Area of passages and driveways (Svsp)
The size of the area of passages and driveways is determined after the adoption of the mechanization option and depends on the type of hoisting and transport machines used in the technological process. If the width of the working corridor of machines working between the racks is equal to the width of the rack equipment, then the area of passages and driveways will be equal to the cargo area or 90% of it.
3. Areas of receiving and picking areas (Spr and Skm)
where A2 is the share of goods passing through the warehouse acceptance area,%, A3 is the share of goods to be picked at the warehouse,%, q is the aggregated indicators of design loads per 1 m2 at the receiving and picking areas, t/m2, tpr - - the number of days the goods are in the receiving area, tkm -- the number of days the goods are in the picking area, Cp -- approximate cost 1 ton of goods stored in the warehouse.
4. Area of jobs Sp.m.
The workplace of the warehouse manager with a size of 12 m 2 is equipped near the picking site with a maximum possible review storage room.
If the warehouse will check the quality of the goods, then the workplaces of the relevant personnel will be equipped near the acceptance site, but away from the main cargo flows.
5. Area of acceptance expedition (Spe)
An acceptance expedition is organized to place the goods received in non-working hours. Therefore, its area should allow to place such a quantity of goods that can arrive over the weekend. The size of the area of the acceptance expedition is determined by the formula:
tpe - the number of days during which the goods will be in the acceptance expedition; Cp - the approximate cost of 1 ton of goods stored in the warehouse; qe - weight 1 m3, t/m2.
6. Area of the departure expedition (Soe)
The area of the dispatch expedition is used for the acquisition of shipping lots. The size of the area is determined by the formula:
toe - the number of days during which the goods will be in the dispatch expedition; Cp - the approximate cost of 1 ton of goods stored in the warehouse;
The procedure for determining the need for cargo and storage space.
When making design decisions for new construction or reconstruction of existing (previously built) warehouses, it is necessary to determine the need for storage space, as well as the storage capacity. The calculation is done like this:
Warehouse space requirement formula
where Sn is the need for storage space (warehouse capacity); N - the standard of warehouse space (capacity of warehouses) per 1 thousand rubles inventory; Q - the stock of goods to be stored in this warehouse.
Determination of the required cargo area can be calculated using the following formula: Sn=Q*K1/K2*h where S n- required area for storage of goods, m 2 ; Q- required storage volume, m 3 ; K1- coefficient of uneven receipt of goods; K 2 - utilization rate of storage space; h- warehouse height.
Warehouse systems in logistics
Lecture plan
1. The main functions of the warehouse system.. 1
2. Classification of warehouses. 2
3. Indicators of the warehouse. 4
4. Determining the size of warehouse space. 6
5. Determining the need for warehouse equipment and lifting and transport mechanisms. eight
Main functions of the warehouse system
Stock- a building, structure, device designed for the acceptance and storage of various material assets, preparing them for production consumption and uninterrupted supply of them to consumers.
The main functions of the warehouse include the following:
1. Accumulation of the necessary reserves of fuel, raw materials, materials, products, etc.
2. Ensuring the safety of material assets.
3. Implementation rational organization loading and unloading and inside warehouse work with minimal cost labor and Money;
4. Proper use of warehouse space and volumes and rational operation of intra-warehouse equipment;
5. Implementation of the proper preparation of inventories for production consumption;
6. Transformation of the production assortment into a consumer one in accordance with demand - the creation of the necessary assortment to fulfill customer orders.
7. Warehousing and storage allows you to equalize the time difference between output and consumption and makes it possible to carry out continuous production and supply based on the created inventory.
8. Unitization and transportation of goods. Many consumers order less-than-wagon or less-than-trailer shipments from warehouses, which greatly increases the costs associated with the delivery of such goods. To reduce transportation costs, the warehouse can carry out the function of combining (unitization) of small consignments for several customers, until the vehicle is fully loaded.
9. Provision of services. Providing customers with various services that provide the company with a high level of customer service, these include:
Preparation of goods for sale (packing products, filling containers, unpacking, etc.)
Checking the functioning of instruments and equipment, installation
Giving products presentation, pretreatment (e.g. wood)
· Forwarding services, etc.
10. Promoting the correct use of materials, rational use waste, as well as containers, etc.
Warehouse classification
Warehouses industrial enterprises and firms are classified as shown in Figure 1:
Warehouse performance
An analysis of the operation of existing warehouses, as well as the choice of the most profitable option for warehouses under construction and reconstruction, is carried out according to the main groups of technical and economic indicators:
Ø volume of work of warehouses;
Ø resource turnover rate;
Ø efficient use of warehouse space and volumes;
Ø the use of handling equipment (idle rolling stock under cargo operations);
Ø labor productivity, degree and level of labor mechanization;
Ø quality of customer service;
Ø the amount of investment in storage facilities;
Ø the cost of processing one ton of cargo;
Ø payback period of investments.
Indicators of the volume of work of warehouses and the speed of turnover characterize the intensity of work of warehouses and include warehouse turnover and freight turnover, specific warehouse turnover, material turnover ratio.
Warehouse turnover- amount products sold for the corresponding period (month, quarter, year) from individual warehouses as a whole. This is natural indicator, which characterizes the complexity of the work of warehouses. It is calculated by the number of released (sent) materials for a certain time (one-way cargo turnover).
Besides, in warehouse logistics the concepts of cargo flow and cargo processing are used.
Cargo traffic- is determined by the amount of cargo passing through the section per unit of time.
Cargo handling- includes the number of transshipments in the course of cargo movement.
Attitude this indicator to the cargo turnover of the warehouse is characterized conversion factor, which can reach a value of 2 or more. The lower this ratio, the better organized technological process warehouse work.
There is also a coefficient of unevenness K n of the receipt (release) of goods from the warehouse, which is equal to:
,
where Q max is the maximum receipt (release) of cargo for a certain period; Q cf - the average receipt (release) of cargo for the same period.
The specific warehouse cargo turnover is equal to:
,
where Ftot is the total storage area, including the areas of closed warehouses, sheds and open areas.
The material turnover ratio is the ratio of the annual (quarterly) turnover of the material to its average balance in the warehouse for the same period.
Indicators characterizing the efficiency of the use of warehouse space and volumes include the following values:
- warehouse utilization rate:
where f floor is the usable area of the warehouse occupied by stored resources;
- the average load per 1 m 2 of storage space is determined by the coefficient:
where Q xp is the amount of stored material in the warehouse, t;
The ratio of the useful volume of the warehouse V floor, occupied by resources, to the total volume of the warehouse V total is characterized by the coefficient:
An indicator of the intensity of use of warehouse space is the so-called cargo density:
where Q g is the annual turnover of the warehouse.
The indicators of the use of material handling equipment are as follows:
The coefficient of use of the mechanism for carrying capacity:
where q f is the mass of the transported cargo; q n - nominal load capacity of the mechanism;
The coefficient of use of the mechanism by time:
,
where T f is the time the mechanism is in operation; T total - the total time of the warehouse.
The actual idle time of the rolling stock under cargo operations is determined by the formula:
,
where q under - the amount of cargo in tons to be processed (loading, unloading); Qh mech - hourly productivity of mechanisms.
The indicators characterizing the productivity of warehouse workers and the degree of labor mechanization are as follows:
Labor productivity of one worker per shift:
where Qtot is the total amount of processed resources for a certain period of time; m - the number of man-shifts spent on the processing of resources for the same period;
The degree of coverage of workers by mechanized labor:
,
where R m - the number of workers performing work in a mechanized way; P - the total number of workers employed in loading and unloading operations;
Level of mechanization of warehouse work:
where Qtot is the total amount of work, including the amount of mechanized work; Q - the amount of work performed manually.
The cost of warehouse processing of one ton of resources is determined by the formula:
,
where Сtot is the total value of annual operating costs, rub.; Qtot is the amount of recycled resources per year, i.e.
The total annual operating costs are calculated as follows:
where З - annual expenses for wages workers servicing machines and devices; E is the annual cost of electricity and fuel, rubles; M - annual expenses for auxiliary (cleaning, lubricants, etc.) materials, rub.; Am - annual deductions for depreciation and repair of machines and mechanisms, rub.; Ac - annual deductions for depreciation and repair of warehouse and other structures and devices, rub.
Determining the size of storage areas
There are general, useful (working) and additional area of warehouses. The total warehouse area Ftot is determined by the formula:
where f floor- usable area of the warehouse, i.e. the area occupied by directly stored resources (racks, stacks, bins, bunkers and other devices for storing these resources);
f pr- the area occupied by acceptance and release sites;
f sl– office space (occupied by office and other office space);
f about- the area occupied by stationary handling and other equipment (lifts, conveyors, etc.);
f aux- auxiliary area, i.e. the area occupied by driveways and walkways.
The useful area of warehouses for metals, hardware, tools, spare parts, equipment, electrical, chemical and other materials and products is determined in two ways:
By way of loading per 1 m 2 of the area of the warehouse;
Using the volume fill factor.
The method of loading per 1 m 2 of the floor area is more convenient and simple. However, it can be used when the load per 1 m 2 of area is known for this type of resource. The calculation formula for determining the usable area of the warehouse in this case is as follows:
where q zap- the value of the established stock of the corresponding type of resource in the warehouse;
q day – average daily consumption of resources;
t xp- the period of storage of resources in the warehouse.
Table 1
The value of σ for various warehouses
Under volume fill factor β v is the volume ratio V 1 resources that fit in a stack, bin, rack, etc., to their geometric volume V, i.e.:
The value of this coefficient is always less than one. Coefficient β v characterizes the density of bookmarking one or another type of resource in the corresponding devices for its storage. Using it, you can determine the capacity of any warehouse equipment q about for storing resources (cells, racks, stacks, bins, bins, etc.) according to the formula:
where V about- the geometric volume of the corresponding storage equipment, m 3;
γ is the share of a certain type of resource.
For equipment (racks, bins, bunkers) that has a simple three-dimensional shape (cubic, prismatic, parallelepiped, etc.), the capacity is calculated by the formula:
where l– the length of the associated resource storage equipment; b- width this equipment; h- the height of this equipment.
Knowing the quantity q zap resources to be stored, required amount of equipment n(cells, racks, bunkers, bins or stacks) is determined by the formula:
If the overall dimensions of the equipment for storing resources and its required quantity are known in the plan, it is possible to establish the usable area for storing these resources:
,
Having thus calculated the usable area for storing certain types of resources and summing up the obtained values, we obtain:
,
The area of acceptance and sorting and release sites is calculated based on the storage of the average daily size of incoming and outgoing resources and the specific load per 1 m 2 of these sites.
In warehouses with a large volume of work, acceptance and release sites are arranged separately. The required size of the acceptance area is determined by the formula:
where Q g– annual inflow of resources, t; q cf– average daily flow of resources to the warehouse, t; σ 1 - load per 1 m 2 of area (taken approximately 0.25 of the average load per 1 m 2 of usable area in the warehouse, depending on the type of stored resources), t / m 2; K - coefficient of uneven receipt of resources to the warehouse (with rational loading of the warehouse K = 1.2, ..., 1.5); t– the number of days the resources are at the receiving site.
The size of the release area is determined by a similar formula.
In large warehouses, instead of separate, relatively small receiving and discharging areas, expeditions for receiving and discharging goods can be organized, which are equipped with weighing devices, as well as the necessary lifting and transporting, packaging and other equipment.
The service area of warehouses includes office and necessary household appliances (dressing rooms, washrooms, latrines, eating rooms, smoking rooms, etc.). The area of the warehouse office is calculated depending on the number of employees. With a staff of 3 people, the area of \u200b\u200bthe office is taken at 5 m 2 for each person, from 3 to 5 - 4 m 2 each, with a staff of more than 5 - 3.25 m 2 each.
The area occupied by handling equipment and other devices (lifts, conveyors, pumps, fans, etc.) is calculated based on the dimensions of this equipment in the plan and the passages of the attendants.
The auxiliary area of the warehouse includes the area occupied by aisles and driveways. The dimensions of aisles and driveways in warehouses are determined depending on the size of the resources stored in the warehouse, the size of the cargo turnover, and the type of lifting and transport mechanisms used to move the resources. The main aisles, where the main vehicles move, must be checked for the possibility of free rotation of floor handling vehicles (trolleys, loaders, etc.) in them. In necessary cases, they must also be calculated for the oncoming movement of mechanisms. For this purpose, use the formula:
A=2B+3C,
where A is the passage width, cm; B is the width of the vehicle, cm; C - the width of the gaps between vehicles, between them and racks (stacks) on both sides of the passage (assumed to be 15-20 cm).
The resulting calculated data constitute the total area of the warehouse.
When choosing a new warehouse and when analyzing the operation of an existing one, the calculation of the area of the warehouse and auxiliary premises, as well as their analysis, is of paramount importance.
The total area of the warehouse includes:
Useful area intended for storage of material;
Area for acceptance and release areas;
Office space occupied by office and other office space;
Auxiliary area for driveways and approaches.
Useful area of the warehouse can be determined in two ways: by the method of loading per 1 m 2 of the floor area and by the method of the filling factor of the volume.
The first method is the most convenient and simple.
The calculation formula looks like:
where - the value of the established stock of the corresponding material in the warehouse, t; - load per 1 m 2 of floor area, t (the value is taken from reference books).
With the help of the filling factor of the volume of any equipment for the storage of materials and products is determined by the formula:
,
where is the geometric volume of the corresponding equipment, 1 m 3; - specific gravity of the material or product, t / m 3; - coefficient of volume filling (packing density).
Knowing the amount of material to be stored, it is possible to calculate the required amount of equipment n using the formula:
Cargo storage equipment can be subdivided according to the type of stored materials: for the storage of bulky, packaged, bulk, liquid and gaseous cargoes in accordance with their physical condition and characteristics.
Piece cargo can be stored in warehouses with stacks or on racks, the types and parameters of which depend on the stored cargo, as well as the purpose of the warehouse, cargo processing technology, shelf life and other factors.
Bulk cargo is stored in open storage areas in stacks and trenches of various shapes and closed warehouses, and in case of small stocks - in bunkers of various shapes.
Liquid cargoes can be stored in warehouses in containers (barrels, bottles, drums) and in bulk.
By multiplying the overall dimensions of the equipment received by the required quantity, the usable area of the warehouse for storing this type of material is determined.
The total usable area of the warehouse is obtained by summing the usable area intended for the storage of certain types of goods.
Acceptance area determined by the formula:
,
where is the annual receipt of material, t; k - coefficient of non-uniformity of receipt of material to the warehouse (seasonality index); t is the number of days the material is at the acceptance site; - load per 1 m 2 of the floor area of the site (assumed to be 0.25 of the average load per 1 m 2 of the floor area in the warehouse).
The area under the release area is determined by a similar formula. In warehouses with a small amount of work, the receiving and shipping areas can be combined.
service area calculated according to the number of employees. With a warehouse staff of up to three people, the office area is taken at 5 m 2 for each person; from 3 to 5 people - 4 m 2 each; with a staff of more than 5 people - 3.25 m 2 each.
The auxiliary area depends on the dimensions of the vehicles with which the warehouse is equipped. AT general view the formula for calculating the area for passages and driveways is as follows
,
where A is the width of the vehicle, m; B - the width of the gap between the vehicles and between them and the racks, m.
The height of the warehouse premises is taken from the floor level to the tightening of the trusses or rafters from 3.5 to 5.5 m. If the warehouse is equipped with an overhead crane, then its height can reach 8 m.
