Calculation of the area of storage of goods in a warehouse. Determining the area of an open warehouse. Technical and economic indicators evaluating the efficiency of the warehouse

23.02.2023

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 etc- 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 vsp- 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:

way of loading per 1 m 2 of the warehouse area;

using the 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- the width of 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 Wed– 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, 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.

Main indicator characterizing a particular warehouse, is the size of the total area of the warehouse.

The total area of the warehouse is divided into the following components:

useful occupied directly with material values or devices for their storage;

operational - the area of receiving and dispatching sites occupied by receiving, sorting, picking and dispensing sites, as well as stacks and racks;

constructive or supportive occupied by walkways, driveways, partitions, columns, stairs, etc.;

official occupied by offices and household premises.

Sizing usable area storage can be done in two ways:

using volumetric meters (light, but voluminous cargo).

According to the first method, the size of the usable area is determined by the formula

Where S floor– usable area of the warehouse, m²;

Z max- the maximum amount of stocks to be stored, t;

q additional– permissible load per 1 m² of usable area of the warehouse, i.e.

In this case, the total area S general is determined by the formula

Where K And- coefficient of use of the total area of the warehouse.

The second method is more accurate. The useful area of the warehouse is determined by the formula

(3.3.3)

Where S st– area occupied by one rack, m²;

n st– number of storage racks, pcs.:

Where n yao- the total number of rack cells required to store the maximum stock, pcs.;

n yast- the number of cells in this rack, pcs.;

(3.3.5)

Where V I- the volume of the rack cell, m²;

g– specific gravity of the stored material, t/m³;

TO O is the filling factor of the cell volume.

Operational area or area of receiving and departure sites is determined by the formula:

(3.3.6)

where is the area of receiving and dispatching sites;

Storage time, 1-2 days;

p is an aggregated indicator of design loads per 1 m2 in expedition premises, t/m2;

k ner - the coefficient of uneven receipt of products at the warehouse; Q year - the annual receipt of goods at the warehouse.

Auxiliary area depends on the size of aisles and driveways in warehouses and is determined depending on the dimensions of the stored products and handling vehicles, as well as the size of the cargo turnover. 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. Passage width, cm:

A=2B+3C, (3.3.7)

Where B- width of the vehicle, cm;

C- the width of the gaps between the vehicles themselves and between them and the racks on both sides of the passage (assumed to be 15 ... 20 cm). In absolute terms, 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. from 3.5 to 5.5 m in multi-storey buildings and up to 18 m in single-storey buildings. Office area warehouse is calculated depending on the number of employees. With a warehouse staff of up to three employees, the area of \u200b\u200bthe office is determined based on the fact that each person has 5 m 2; from 3 to 5 people - 4 m 2 each; with a staff of more than five employees - 3.25 m 2 for each employee. The workplace of the warehouse manager (area 12 m 2) is recommended to be located near the picking area so that there is a maximum overview of the warehouse. If it is planned to check the quality of stored products at the warehouse, then it is recommended to equip the workplaces of the personnel responsible for this near the acceptance site, but away from the main cargo flows.

Space-planning solutions in the warehouse

On-site warehouses are organized for temporary storage of materials, structures, products, equipment and other material resources during the construction of facilities. The volumes of resources to be stored are minimized due to the rational organization of construction, advanced methods of construction and installation work, containerization of construction cargo and other organizational and technical solutions.

They begin to calculate the warehouse economy, having a calendar plan for the production of works, a schedule for the supply of materials, parts and structures, data on the transport used and the distance of transportation of materials from the place of receipt to the construction site.

When designing on-site warehouses, the following tasks are solved:

Determination of stocks of materials, structures and products to be stored;

Eliminate unnecessary loading and unloading operations at the construction site;

Ensure the safety of materials, parts and structures;

Use for loading and unloading, as a rule, assembly mechanisms;

Ensure the lowest cost of warehousing.

Calculation of the area of on-site warehouses for the main types of material resources;

Selection of the type of warehouses and their placement on the construction site.

The calculation of warehouses consists in determining their area, taking into account the acceptance and release areas, driveways and aisles.

The main type of warehouses at the construction site are open areas. They are located in the area of operation of a crane installed to supply goods to a building under construction. Sites for storing structures, wall materials and other resources are located along temporary roads. In places of unloading vehicles on the roads, local widenings are provided.

The main provision that should be followed when determining the amount of materials, parts and structures stored in warehouses is to ensure their minimum stocks, which should ensure uninterrupted operation at the construction site.

Structures intended for the installation of the main frame - reinforcing cages and meshes - are stored directly at the installation sites.

Finishing materials, roofing materials, plumbing and electrical installation equipment must be stored in closed on-site warehouses.

The main leading process in the construction of an office center is concreting, the concrete mixture is delivered and immediately placed into the formwork using concrete pumps. Reinforcing cages are delivered to the construction site ready-made, and small cages are welded on the construction site. Bricks and blocks of cellular concrete are stored in on-site warehouses with a 3-day supply. Finishing materials, expensive equipment and other small inventory and devices are stored in closed warehouses.

Warehouse area is calculated by the number of materials:

Usable area of the warehouse:

Total estimated area of warehouses:

The calculation of the warehouse area is presented in the table (5.1)

Table 5.1 - Calculation of the area of warehouses

Name of parts of products and structures

Total demand, Qtotal

Duration of laying materials T, days

Number of days of supply n

Stock in warehouse Qsp

Storage rate per 1 m3 area q

Useful warehouse area F, m2

Warehouse area utilization factor β

Total warehouse area S, m2

Warehouse dimensions, m

Warehouse characteristics

Window, door blocks

under a canopy

Bricks on pallets

open

fittings

under a canopy

Slag, sand

closed

Coating slabs.,

blocked.

open

closed

Cement-sand. rr

closed

formwork

under a canopy

Foundations

open

Lacquers, paints, plaster

closed

stairs

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, having calculated the usable area for storing 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 A- passage width, cm;

IN- 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).

In absolute terms, 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)

In conditions of financial problems, the work of the economic service, on the one hand, should be aimed at minimizing costs, on the other hand, at increasing the economic efficiency of the enterprise. In this article, we will consider the issues of increasing the economic efficiency of warehouses.

TECHNICAL AND ECONOMIC INDICATORS ASSESSING THE EFFICIENCY OF THE WAREHOUSE

The main functions of the warehouse include:

creation of an assortment in accordance with the need. The function is aimed at providing the necessary material and technical resources (in terms of quantity and quality) of various phases of production;
warehousing and storage. The performance of this function allows you to equalize the time difference between the supply of material resources and their consumption, which makes it possible to ensure a continuous production process and uninterrupted supply of consumers on the basis of the created reserves. The storage of material resources is also necessary in connection with the seasonal consumption of certain materials;
provision of services. In order to provide a higher level of service, warehouses can provide forwarding services, check the functioning of instruments and equipment, prepare materials for production consumption, etc.

To assess the work of the warehouse, technical and economic indicators characterize:

efficient use of warehouse space;
the intensity of the warehouse;
the cost of warehouse processing of goods.

Indicators characterizing the efficiency of warehouse space use

The indicators of this group include:

utilization rate of warehouse space;
utilization rate of the warehouse volume;
traffic density.

Warehouse space utilization ratio (TOS ) is the ratio of usable (cargo) area ( S floor) of the warehouse to the total area of the warehouse ( S total):

TO S = S floor / S total

The area of the warehouse of a trade enterprise, directly occupied by the storage of goods, is 300 m 2, the total area of the warehouse is 1000 m 2.

Warehouse space utilization ratio:

300 m2 / 1000 m2 = 0,3 .

To increase the value of the coefficient, it is advisable for a trading company to consider increasing the number of stored goods or leasing part of the warehouse space or concluding storage agreements with outside organizations.

Warehouse capacity utilization ratio (TOV ) characterizes the use of not only the area, but also the height of storage facilities:

TO V = V floor / V total,

Where V floor - useful volume, determined by the product of the cargo area by the useful height (that is, the height of racks, stacks);

V total - the total volume of the warehouse, determined by the product of the total area by the main height (that is, the height from the floor of the warehouse to the protruding parts of the floor that limit the storage of goods).

(G ) shows how much cargo is located simultaneously on each square meter of usable warehouse space:

G = Zmax / S floor,

Where Zmax- the maximum stock of materials that is stored in the warehouse, i.e.

The specific average load per 1 m 2 of usable area makes it possible to compare the use of storage facilities and their throughput during a year.

Cargo density 1 m 2 of the total warehouse area (M) during the year is determined by the formula:

M = Y year / S total,

where Y year is the annual cargo turnover of the warehouse, i.e.

The annual turnover of the warehouse is 1,000,000 tons, the usable area of the warehouse is 1,000 m 2 .

Cargo density 1 m 2 of the total warehouse area:

1,000,000 t / 1000 m 2 = 1000 t/m2.

The load factor makes it possible to compare the use of storage facilities and their throughput in various years.

Indicators of warehouse work intensity

Indicators of the intensity of work of warehouses are:

warehouse turnover;
warehouse cargo turnover;
inventory turnover rates.

Trade turnover is planned and accounted for in value terms and represents the volume of material assets released from the warehouse to consumers for a certain period.

Warehouse turnover- the ratio of turnover for a certain period (day, month, year) to the average cost of 1 ton of cargo. It is possible to calculate the freight turnover of the warehouse upon arrival or departure of goods (one-way freight turnover).

Calculation formula warehouse turnover (G):

G \u003d T rev / C cf,

where T rev - turnover for a certain period, rub.;

C cf is the average cost of 1 ton of cargo, rub./t.

Warehouse specific cargo turnover (warehouse usable area efficiency) (Good) is the ratio of the warehouse turnover to the usable area of the warehouse. This value shows how many tons of goods that have passed through the warehouse fall on 1 m 2 of the useful area of the warehouse:

Г beats \u003d G / S floor.

The higher this indicator, the better the warehouse works.

Warehouse load unevenness coefficient (To unequal load) is defined as the ratio of the turnover of the most busy month (G, for example, month) to the average monthly warehouse turnover (G avg / month):

To unequal load = G e.g. month / Y Wed / month

The turnover of the busiest month (December) is 10,000 tons, the average monthly warehouse turnover is 5,000 tons.

Warehouse load unevenness factor:

10,000 tons / 5,000 tons = 2.

The warehouse owner should take additional measures to evenly load the warehouse (you need to look for warehouse space tenants, change the supply logistics, etc.).

Warehouse turnaround time (shelf life) shows how much time the stock of inventory items in the warehouse will be exhausted (expressed in days or fractions of a year).

Warehouse turnover (cargo turnover ratio) (K equiv) shows how often the contents of the warehouse are completely updated. This value most fully reflects the intensity of the warehouse. Calculation formula:

K rev = Q offload / ( T × Q size),

Where Q shipped - the number of products shipped for the period T, T;

Q size - the total number of products that can be placed in the warehouse, i.e.

For a month (30 calendar days), 10,000 tons of products were shipped from the warehouse, and it was possible to ship 20,000 tons during this period.

Accordingly, the cargo turnover ratio (K rev):

10,000 tons / (1 month × 20,000 tons) = 0.5.

The higher this coefficient, the higher the intensity of the warehouse.