Calculating the cost of construction work is one of the most important parts of the entire project. Because the estimate helps determine the amount of expenses necessary to carry out all construction and installation work, on which the contract price between the customer and the contractor is based.
Types of estimates
If we consider the entire block of construction and installation work, then estimates covering all objects under construction are called “summary”. And estimates that reflect the cost of one object or type of work are called “object” or “local,” respectively. The site estimate includes several local ones, and it is the main source for calculating the cost of work under the contract for the construction of the facility.
Estimates for installation of ventilation can be classified as local, because a separate ventilation and air conditioning system is designed for each facility under construction. This applies to both public and private buildings and structures, as well as industrial facilities.
The estimate differs from the estimate calculation in that during the calculation, the volume of work, and, consequently, the costs will still be clarified during the development of working documentation or during the construction process.
How to calculate the estimated cost of work
The cost for certain types of construction work is determined by the formula:
Ssmr=PZ+NR+PN, where
- PP – direct costs;
- HP - overhead costs;
- PN – planned savings.
Direct costs
They include:
- Workers' salaries;
- Cost of materials and structures used;
- Expenses for operating the necessary machines and mechanisms.
Salary is calculated using the formula Z=TxZmes/t, where
- T – labor intensity of work, that is, the cost of living labor per unit of time, it is determined according to standards, in man-hours;
- Zmes – average monthly salary of one worker, in rubles;
- t – average monthly working time, in hours;
The cost of the materials used is determined by multiplying the material consumption rate by the current price.
And the operating costs for using machines and mechanisms are calculated by multiplying the rate of time for using this equipment (in machine hours) by the price of one machine hour, which is also calculated using the following formula:
Tsmash-hour=(Zed+Zgod+Zex)xKPR, where
- Zed – one-time costs, that is, the costs of transporting goods by vehicles, and their unloading and loading, in rubles/machine-hour;
- Zgod – annual costs, that is, depreciation;
- Zex – operating costs, that is, wages for mechanics servicing machines, as well as the cost of fuels and lubricants, consumed electricity, etc.;
- Knr – overhead cost coefficient.
Overheads
These are costs aimed at the smooth functioning, management and organization of construction. Determined in several ways:
- Through a percentage of direct costs fixed in federal overhead standards;
- According to the standards in force in a particular construction organization;
- Based on aggregated indicators.
Planned savings
Or estimated profit . These are expenses not directly related to construction work, but ensuring the functioning of the construction site. These are tax deductions, expenses for production development, material incentives, etc. It is calculated based on regulatory documents. Most often it is 12% of the total cost of construction and installation work or 50% of workers’ compensation.
The main methods for calculating estimates
There are several types:
- resourceful – this method allows you to calculate the estimated cost at a given time, by basing it on current prices for the costs of labor, materials and equipment, operation of machines and mechanisms;
- resource-index – it involves additional indexation of construction costs based on the base cost;
- base-index – this method is not similar to the resource-index method in that it involves multiplying the base cost of each item in the estimate by the corresponding index, only after which the total amount is calculated;
- basic compensation – using this method, the problem of estimate calculation is solved, when the base cost can change, taking into account current prices and tariffs during the construction process.
How to calculate estimates for ventilation and air conditioning
Let's move directly to drawing up estimates for ventilation and tell you which collections of prices are best to use for certain types of work.
Any professional estimator knows that repair work should be calculated based on the prices for dismantling and replacing equipment, and installing ventilation. systems - at prices from collections of installation prices.
The collection of State Elementary Estimate Standards (GESN), its 20th part, should be considered as the main collection of state prices for installation, repair and maintenance of ventilation systems.
The estimator can also choose as a basis the 20th part of the territorial and federal prices for ventilation work (TER and FER), however in this case it is better to include the cost of materials and equipment in a separate line or price list.
For the installation of fans, pumps and compressor units, the collection GESNm-07, FERm-07 is used. And for commissioning of ventilation and air conditioning systems you need GESNp-03, FERm-03. Prices for dismantling work on dismantling ventilation shafts, ducts, air ducts and fans are contained in the collections GESNr-65, FERr-65.
Stages of installation of ventilation systems
To properly assess ventilation installation work, it is necessary to clearly delimit all installation stages.
The installation of a ventilation system is divided into:
- Inspection of the ventilation system;
- Dismantling the old ventilation system (if it is a renovation project);
- Assembly of a new ventilation system - air ducts, filters, insulation;
- Installation of supporting structures and final configuration;
- Installation of automation systems;
- Commissioning and testing of the installed system.
Let's consider all types of installation work separately.
Ventilation survey
An examination of the ventilation system to search for various defects is carried out during a special visit of a specialist to the site. The engineer performs an initial inspection of ducts and chimneys, as well as a sanitary and epidemiological visual inspection. After which a report on the results is compiled.
Basic prices for the inspection of all utility networks are contained in Soviet price collections of Specialized Centers from 1990. Appropriate coefficients should be applied to them. But there is a lot of controversy regarding the new editions of prices, and each construction company sets them individually.
Dismantling ventilation
First, a thorough examination is necessary to identify the non-functioning node. And then calculate what work needs to be done and what materials should be spent to replace the defective part of the system. Only after these calculations can the cost of dismantling be calculated.
But if complete demolition of the entire old ventilation system is required, then the price of dismantling will differ significantly from the price of replacing one or more components. After all, complete disassembly of ventilation shafts, air ducts, fans, exhaust pipes and louvres will be required.
The cost of these works can be found in GESNr-65-(28-32) and FERr-65-(28-32). The price of dismantling should also include cleaning and removal of the resulting construction waste.
Regarding the reduction factors for direct costs of dismantling work, guided by MDS-37 clause 3.2, we can say that:
- if the dismantled equipment is subject to subsequent use, with removal from its place, disassembly and preservation for the purpose of storage, then the coefficient will be 0.7;
- if the equipment is to be used, but without storage, the coefficient will be 0.6;
- if the equipment is not subject to use, with disassembly and cutting into parts, the coefficient is 0.5;
- the same thing, but without disassembly, for ejection - 0.3.
Installation of supply ventilation
The supply ventilation system consists of an extensive network of air ducts and an air supply unit. Air is supplied to the room after passing through purification, humidification, cooling, or heating systems. This is done through the use of various air ducts, filters, fans, coolers, and heaters.
First, the air ducts are laid and the supply chambers are installed, and then the supply units, brackets for ventilation equipment are installed, louvers and ventilation grilles are installed, as well as air heaters or water heaters. The cost for these types of work can be found in the price collections GESN-20-(01-06), FER-20-(01-06) and TER-20-(01-06).
Afterwards, it is necessary to install an automation system that will allow you to control the installation, regulating the temperature and air flow. This issue will be discussed further.
Exhaust ventilation
Ventilation systems operating on the exhaust principle are installed in a large number of objects, such as various enterprises, retail and office premises, and residential buildings. They are designed to remove various pollutants from the air - smoke, burning, soot, dust, steam, etc. The simplest example is that an extractor hood is installed in the kitchen or bathroom to cleanse the room of soot, moisture and unpleasant odors.
Installation of exhaust systems is carried out in two ways: either a local system - for each room, or a general system - for all rooms. It is considered beneficial to install local exhaust systems, which are divided into semi-open and open. In semi-open systems, exhaust air is suctioned using exhaust hoods. And in open ones, side suction is used.
The easiest way to install general exchange ventilation systems is to install axial fans.
For better air suction in industrial premises, ventilation shafts used for exhaust are usually laid under the floor.
Prices for installation of passage units for exhaust ventilation shafts, umbrellas, deflectors and other equipment can also be found in the collections GESN-20-(01-06), FER-20-(01-06) and TER-20-(01-06).
Supply and exhaust ventilation complex
This type of ventilation has proven itself in large industrial facilities and institutions. For this purpose, special equipment is installed, with the help of which it is possible to artificially stimulate air circulation in the room, and with the help of diffusers, the uniform distribution and movement of air flows occurs.
The set of equipment for this type of ventilation includes noise suppressors, vibration isolators, filters, air heaters, air heating and dust collection units, since due to their operation not only cleaning and cooling occurs, but also heating of the air.
At large facilities, it is justified to use such components of systems operating on the principle of supply and exhaust, such as recuperators that save energy consumption, as well as humidifiers, dehumidifiers and air coolers, etc. As in the previous sections, prices for these types of work should be found in GESN, TER and FER, chapter No. 20 and GESNm, TERm and FERm, chapter No. 07.
Ventilation automation
The simplest versions of automation systems are designed to regulate air temperature and fan speed. They can also protect heaters from overheating and freezing at extreme temperature levels.
And current automation systems for ventilation regulation and control allow operation on a timer, and also have a connection to the “smart home” system. They are equipped with a control panel and a screen on which all information regarding the operation of the system is displayed.
Such systems are often installed by contractors on a turnkey basis and equipped with electrical panels to control the operation of the units.
Commissioning of ventilation systems
After installing the ventilation system, it is necessary to carry out commissioning work to put the system into operation. This is an absolutely necessary stage of work, allowing us to identify and eliminate shortcomings in the installation of the entire ventilation system.
To do this, a trial run of the ventilation system is carried out and the equipment is examined for compliance with its nominal parameters. The quality of installation is also checked and final certification is carried out.
Prices for commissioning work carried out after installation of ventilation systems can be found in the collections GESNp-03, FERp-03 and TERp-03.
In all the variety of calculations and calculations compiled according to state prices, estimates for ventilation and air conditioning systems (including drugs and compressors for their repair, maintenance, commissioning and design) do not occupy such a significant role, despite the fact that they can vary significantly. On the Internet you can find quite a few examples of ventilation estimates compiled in Grand Estimate or other software packages. These sample estimates differ from each other, first of all, in the functional purpose and selection of work performed: ventilation repairs usually include prices for dismantling and replacement, and installation of ventilation systems - prices from installation collections. Another classification criterion may be the type of systems being installed, for example, calculations for supply and exhaust ventilation or installation of air conditioners of a specific type.
If we talk about government prices used in drawing up estimates for ventilation and air conditioning, the most comprehensive and important collection is, perhaps, the GESN in part 20, which gives a clear idea of the materials and technologies used during installation, repair or maintenance. When estimating the installation of ventilation and air conditioning systems in territorial and federal prices (FER), the estimator takes into account the cost of the installed equipment in the estimate as a separate line (according to the price list or price bulletin), unless, of course, this is already included in the price. So, in part 20 of the collections there are prices for installing radial and axial fans, and the cost of the first is included in the price, but the second is not. When carrying out ventilation work, the project quite often requires the installation of air ducts made of aluminum, sheet and galvanized steel of various thicknesses, the installation of which is also carried out according to the characteristics of the technologies used. From the same part you can take prices for the installation of various types of cooling systems: ejection air conditioners, air heaters and receiving units.
To install fans and air conditioners, a collection of prices for installation work is often used in Part 7, which discusses the algorithm for calculating material and labor costs for these types of work. As a rule, assembly collections take into account only the costs of auxiliary materials and the costs of paying personnel and operating machines. The cost of installed fans and other equipment is taken into the estimate from the price list or invoice minus VAT and with the addition of transportation and procurement costs. As an example, consider an estimate for ventilation, compiled using the Grand Estimate software, at base prices per unit of work performed.
Sample of drawing up an estimate for ventilation work in TER-2001 Krasnodar
| Rationale | Name | Col. | Basic Salary | EkMash | Salary Fur | Total |
| TER 20-01-001-05 | Laying an air duct made of sheet steel and aluminum with a thickness of up to 0.6 mm and a diameter of 355 mm | 100 m2 of air ducts | 1078.90 | 127.08 | 4.46 | 1712.76 |
| TER 20-01-001-01 | Laying an air duct made of sheet steel and aluminum with a thickness of up to 0.5 mm and a diameter of 2400 mm | 1178.38 | 155.32 | 5.39 | 1904.35 | |
| TER 20-02-009-01 | Installation of an umbrella over a round steel shaft with a diameter of up to 200 mm | 1 PC. | 3.46 | 1.41 | 0.00 | 8.17 |
| TER 20-02-001-01 | Installation of an air distributor designed to supply air, weighing 20 kg | 1 air distributor | 9.46 | 3.03 | 0.00 | 21,15 |
| TER 20-02-004-15 | Installation of a fire-retarding valve with a perimeter of 1600 mm | 1 valve | 29.27 | 2.98 | 0.00 | 510.36 |
| TER 20-02-013-01 | Installation of a passage unit for an exhaust ventilation shaft with a pipe diameter of 250 mm | 10 knots | 192.34 | 3.33 | 0.00 | 273.44 |
| TER 20-02-015-10 | Installation of a ventilation silencer type GTP with a cross section of 400*400 mm | 1 PC. | 12.94 | 2.83 | 0.00 | 29,34 |
| TER 20-02-019-01 | Installing a bracket for ventilation equipment | 100 kg product | 44.37 | 10.25 | 0.00 | 1021.59 |
| TER 20-03-002-02 | Installation of an axial fan weighing 0.05 t | 1 PC. | 41.77 | 13.37 | 0.10 | 57.93 |
| TER 20-06-015-01 | Installation of fan units with a capacity of 10 thousand m3/hour | 1 unit | 90.86 | 23.36 | 0.73 | 207.34 |
| TERr 65-30-2 | Dismantling an air duct made of steel 0.9 mm thick with a diameter of 320 mm perimeter | 100 m2 of air duct surface | 272.92 | 30.82 | 6.68 | 303.74 |
| TERr 65-30-3 | Disassembling an air duct made of steel 0.9 mm thick with a diameter of 497 mm perimeter | 100 m2 of air duct surface | 219.56 | 30.82 | 0 | 6.68 |
| TER 20-02-018-01 | Installation of flexible inserts to a radial fan | 1 m2 | 40.37 | 0.96 | 0.00 | 46.56 |
Explanations for example.
This sample contains prices for installation or dismantling of equipment without indicating specific brands or close analogues from the collection of basic prices (TSSP) of the Krasnodar Territory. If the price does not take into account the cost of materials and equipment, they must be added to the estimate in a separate section or after the prices for installation or repair.
The specified list of prices is presented as an example of costing of ventilation work in unit prices at prices of the base period. According to the technical conditions of a particular project, a list of direct or applied prices is selected, as well as coefficients that take into account the conditions for construction and installation works. A correctly drawn up estimate for ventilation and air conditioning based on the results is close to the cost of installation and repair of these types of equipment and helps to determine the costs of the work performed even before the start of their implementation.
An example of an estimate for ventilation - installation
Download an example of an estimate for installation work on ventilation systems, incl. laying air ducts, installing ventilation equipment and automation devices.
What specific work may be included in the estimate for installation of ventilation? What norms for the consumption of auxiliary costs and materials man-hours should be based on? Are there any standards for these costs? In our article we will try to answer these questions.
List of works
First, let's decide what specific work can be included in the estimate.
Main
- preparation and development of project design documentation.
See: the project must be justified by calculations confirming its absence and the operability of the redundant performance of the designed system. Of course, the client is interested not only in efficiency, but also in saving his own money.
- If necessary, dismantling the dilapidated ventilation system, partial dismantling of partitions, punching shafts in the ceilings.
- Installation of air ducts, air intakes, grilles and supply hoods.
- Installation of fans, filters, heaters, air conditioning systems etc.
- A separate item includes estimates for commissioning work on ventilation..
Auxiliary
In addition to the actual dismantling and installation, the contractor will have to:
- equipment and transportation of materials.
- Loading and unloading operations (as well as using equipment, the work of which is paid separately).
- Construction of temporary sites, scaffolding, etc.
- In the absence of a stable power supply at the beginning of the work, supply the construction site with its own electricity generation.
Regulations
When drawing up an estimate, two documents are needed:
- National elemental estimate standards (GESN), section 20. They allow you to estimate the need for resources (the same man-hours, duration of equipment operation, number of rivets, etc.).
- Federal unit rates (FER), section 20. This contains the approximate cost of each work done during installation or dismantling. Prices are a recommendation.
See: in addition to FER, there are also Territorial Unit Rates (TER), compiled taking into account the specifics of local conditions (logistics, road conditions, seasonal temperatures, etc.). Both FER and TER can be used as justification for drawing up estimates.
Here are short excerpts from both documents.
GESN
In accordance with this document, for laying an air duct with a non-specialized wall area of 100 m2 with a wall thickness of 0.5 mm and a diameter of up to 200 mm, the following resources will be required:
| Type | Quantity |
| Workers' time spent | 167.86 man-hours |
| Driver labor costs | 1.3 man-hours |
| The operating time of a manual winch with traction hardening is up to 2 thousand kilograms | 0.39 machine hours |
| Arc welding machine operating time | 1.79 machine hours |
| Operating time of a truck with a carrying capacity of up to 5 thousand kilograms | 0.78 machine hours |
| Duration of operation of a truck crane with a lifting capacity of up to 10 thousand kilograms | 0.52 machine hours |
| Metal consumption for duct walls | 100 m2 |
| Consumption of construction bolts, nuts and washers | 0.015 t |
| Consumption of welding electrodes | 0.00045 t |
| Consumption of sealing mastic | 0.00501 t |
| Consumption of asbestos cord | 0.00089 t |
| Consumption of rubber gaskets | 8 kg |
FER
And here are the estimated costs, on the basis of which a local estimate for ventilation is drawn up, from the Federal Unit Prices of 2001. As an example, we will use the same air duct with a wall thickness of 0.5 mm, an area of 100 m2 and a diameter of up to 200 mm.
Let us clarify: the materials included in the project are a separate cost item. Unaccounted for materials are, for example, replacing a welder's mask with accidentally crushed glass or an adjustable wrench broken when tightening flanges. Because most installation work is done with one’s own hands, using hand tools, the anthropogenic factor will be the main item of unaccounted costs.
Example
We hope that the instructions for preparing estimates are generally understandable to the reader. Now let's study an example. An example for us will be the estimate for a ventilation device compiled by the metropolitan company Smeta-Moscow; Due to the limited volume of our material, we will present only a small excerpt from its text.
| Position number | Justification (number and code of the regulatory document) | Name of cost item | Quantity | Non-specialized payment price, rubles | Cost of car operation, rubles | Labor costs of workers, man-hours |
| 1 | TER 20-06-002-01 | Installation of standard supply chambers with a capacity of up to 10,000 m3/hour without an irrigation system | 1 | 1045,98 | 155,29 | 50,27 |
| 2 | TER 20-03-001-02 | Installation of a radial fan weighing up to 0.12 t | 1 | 180,28 | 21 | 10,35 |
| 3 | TER 20-02-019-01 | Installation of brackets for ventilation equipment (100 kg of product) | 0,08 | 1316,68 | 16,05 | 0,55 |
| 4 | TER 20-02-003-10 | Installation of metal louvered control ventilation grilles measuring 150x150 mm | 15 | 36,1 | 8,38 | 18,45 |
| 5 | TER 20-01-001-02 | Laying aluminum or galvanized air ducts with a thickness of 0.5 mm and a perimeter of up to 600 mm (100 m2 of surface) | 0,025 | 3123,92 | 216 | 4,83 |
| 6 | TER 20-01-001-03 | Laying aluminum or galvanized air ducts with a thickness of 0.5 mm and a perimeter of 800, 1000 mm (100 m2 of surface) | 0,36 | 2890,74 | 172,91 | 63,63 |
| 7 | SCM-300-9066-1 | Galvanized metal air ducts 0.5 mm thick (m2) | 38,5 | 9799 |
Conclusion
We remain hopeful that our material will help the reader navigate the preparation of estimate documentation. As in most cases, you can find additional information in the attached video in this article. Good luck!
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