Introduction
An important measure of warehouse performance is the cost of handling a unit load through that warehouse. To correctly calculate the cost of unit load flow through a warehouse, it would be best to have identified process costs, which would significantly simplify reaching the result. However, enterprises most often have a natural classification of costs. In such a case, an appropriate methodology must be used to allocate natural costs according to keys to individual warehousing phases. The procedure in the presented methodology is as follows
- Identification of natural costs at the most detailed (analytical) level and warehouse parameters needed for cost accounting and allocation.
- Determination of possible cost keys, e.g., (area, number of employees, asset value, number of external transport means.
- Grouping costs into items that can be allocated using a given cost key.
- Summing up the cost values in a given “key” group.
- Identifying the main costs of warehousing phases: receiving, storage.
In the first phase, we identify costs by type for the warehouse for which we want to examine the pallet flow cost. The flow cost will be defined by formula 1:
where:
Kopm – cost of handling one pallet unit load by the warehouse [PLN/plu],
kppjł – cost of receiving a pallet unit load [PLN/plu],
kspjł – cost of storing a pallet unit for a day [PLN/plu/day],
rd – rotation in days,
kwpjł – cost of picking and issuing a pallet unit load,
STEP 1 Identification of natural costs at the most detailed (analytical) level and warehouse parameters needed for cost allocation and assignment.
Tab. 1. Costs by type for warehouse xxx
| cost by type | value |
| depreciation of fixed assets | 28000 |
| stamp duty, official, and handling fees | 10000 |
| property tax | 50000 |
| other fees | 7000 |
| other services | 85000 |
| contributions to the employee social benefits fund | 30000 |
| benefits for protective work clothing | 7000 |
| employee insurance benefits | 240000 |
| employee benefits – training | 8000 |
| employee health and safety benefits | 12500 |
| other employee benefits | 3000 |
| mobile phones | 2000 |
| landlines | 3000 |
| property insurance – buildings and structures | 3000 |
| other property insurance | 9000 |
| property insurance – transport means | 2000 |
| property protection services | 35000 |
| repair services – buildings and structures | 5000 |
| repair services – transport means | 75000 |
| employment remuneration | 1200000 |
| consumption of spare parts | 13000 |
| heat energy consumption | 20000 |
| electricity consumption | 45000 |
| consumption of housekeeping/admin materials | 15000 |
| consumption of office materials | 22000 |
| packaging consumption | 80000 |
| liquid fuel consumption | 95000 |
| solid and gas fuel consumption | 23000 |
| cold water consumption and sewage | 9000 |
We know the following about the analyzed warehouse:
Tab. 2. General warehouse characteristics
| Name | value | unit |
| warehouse area | 7 500 | sq m |
| number of employees | 27 | people |
| warehouse turnover | 300 000 | plu/year |
| number of storage locations | 4 500 | pcs |
| value of warehouse assets | 5 200 000 | pln |
Tab. 3. Characteristics of the receiving zone
| Receiving zone | value | unit | share (%) |
| zone area | 500 | sq m | 6.67% |
| number of employees | 7 | people | 25.93% |
| whse turnover – received plu. | 120 000 | plu/year | 40.00% |
| value of zone assets | 700 000 | pln | 13.46% |
Tab. 4. Characteristics of the storage zone
| Storage zone | value | unit | share (%) |
| zone area | 6 000 | sq m | 80.00% |
| number of employees | 4 | people | 14.81% |
| number of storage locations | 4 500 | pal spaces | 100.00% |
| value of zone assets | 3 500 000 | pln | 67.31% |
Tab. 5. Characteristics of the picking and shipping zone
| Picking and shipping zone | value | unit | share (%) |
| zone area | 1 000 | sq m | 13.33% |
| number of employees | 16 | people | 59.26% |
| whse turnover – issued plu. | 180 000 | plu/year | 60.00% |
| value of zone assets | 1 000 000 | pln | 19.23% |