Differentiate Between ESTIMATION

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Text of Differentiate Between ESTIMATION

. CE 2402 ESTIMATION & QUANTITY SURVEYING Differentiate between B E Civil Engg 4th Yr 7th SemUnit 1 ESTIMATE OF BUILDINGS

1Differentiate between Centre Line Method & LW-SW Method

#Parameter CENTRE LINE METHODLW-SW METHOD

aFundamental Requirement The element to be estimated should be SYMMETRICAL about the VERTICAL Axis and also about the PLAN Axis in the given direction Symmetry is NOT Required

bBasic Premise / Drawing requiredthe LINE Plan ( here also full wall plan will be required but LINE Plan is fundamental data ) the FULL Wall Plan

cCalculation MethodFull Perimeter of centre line length of IDENTICAL Walls is calculated as the Base MeasureLong Walls and Short Walls are grouped separately

dif walls of 2 DIFFERENT THICKNESSES are involvedthe walls of different thicknesses are taken separately. TOTAL of lengths of centre lines of each thickness are added separately walls of different thicknesses are taken separately

eComparative Comment*for regular plan shapes, this is a faster method *With the value of TOTAL centre line length, many other quantities can be calculated easily each element requires separate calculations making it a bit lengthy and laborious

fwhich method When? When all elements are SYMMETRICAL about VERTICAL AxisNo such specific case

2Differentiate between Supplementary Estimate & Revised Estimate

#Supplementary Estimate Revised Estimate

aDefn Supplementary Estimate is a DETAILED Estimate prepared when ADDITIONAL Works are required to be executed in addition to the works already planned This is the estimate of the works over and above the original list of works Revised Estimate is required when the original types and quantum of works face significant deviation either in terms of Specifications or Quantity or Total Budgetary Limits or all of these Even if the Quantity of the works has to be reduced significantly, then a Revised Estimate is required

bWhen When additional works are to be executed When QLy / QTy / BOTH of the original works are changed significantly

cR E prepared if original estimate is severely wrong & requires corrections

3Differentiate between Lump Sum Estimate & Item Rate Estimate

#Lump Sum Estimate Item Rate Estimate

aDefn Total estimate based NOT on proportionate quantities as arrived from the drawings ;;; Instead contractor quantifies the resources required and costs based on visual inspection and past experience;; agrees to a FIXED Amount LUMP SUM The estimate is prepared based on the quantity of each work item which is quantified proportionately as per the drawings

bRATESRates are NOT Applied for any work itemRate is applied for every work item and each work item is estimated in proportion to its INDIVIDUAL quantity

cTotal LS includes all expected and unexpected Overheads, Contingencies, Profit Margin etc. Overheads, Contingencies, Profit Margin are all added to the total estimate arrived from the individual work estimates

4

Differentiate between Contingency & Overhead

Parameter Contingency Overhead

aDefn Contingencies represent INCIDENTAL expenses ** cannot be apportioned to any one particular work ** arises due in relation with the execution of the works Overhead expenditures include all those expenditures which are not technically proportionate to the type or quantum of works Overheads are due to various ADMINISTRATIVE requirements

BQuantum Usually Contingencies are estimated at 3 to 5 % of the Total Estimated CostOverheads are proposed at about 5 to 10 % of the Total Estimated Cost

EXPECTED UNWANTED but UNAVOIDABLE Expenses and cannot be estimatedExpected Can be estimated to a fair degree of accuracy but cannot be calculated accurately

cTypes Overheads are classified into 2 types

1 GENERAL Overheads

2 JOB Overheads

dExamples .** Expenses due to Severe Rains ** Delays / Losses due to strikes ** Delays / Losses due to Law & Order problems GENERAL Overheads ** Office establishment ** Stationary** Travel between HO and Sites ** Telephone** Staff Quarters Rent, etc. ** Advertisements

.JOB Overheads are due to ** Extra Staff for the Project ** Material Handling and Storing ** Repairs and Maintenance Charges ** Labour Amenities ** Workmens Compensation, Insurance, ESI ** Interest on Investments** Losses of Interest due to Disbursal of Advance Payments

5Differentiate between BoM & BoQ

#Feature BoM Bill of Materials BoQ Bill of Quantities

aDefn The BoM is a list ** shows all parts and components related to a drawing with the corresponding technical ID marks also the quantities for each item are mentioned BoQ is a list Shows the quantities of Raw Materials. Manufactured Part, Labour, Tools & Plants, Machine Hours and all such requirements related to the given works

bPurpose so that the (purchase) manager can easily place orders as per exact specifications assumed by DESIGNER This list helps the Project Manager to estimate the Project Budget and arrive at the other parameters such as Contingencvies, Overheads, and all other INDIRECT costs

cHowever many practitioners use both the terms SYNONYMOUSLY

6Differentiate between Prime Cost & Provisional Sum

#Prime Cost Provisional Sum

aDEfn Prime Cost PC is the basic cost to be spent / paid for buying or manufacturing a given item Provisional Sum is the APPROXIMATE amount provided in the estimate in the beginning for works which cannot be defined and quantified at that stage.

bINCLUDESIn manufacturing, PC refers to the total direct costs towards raw materials, labour, packaging. transporting, etc. PS is allowed for work items which cannot be accurately taken off or which requires SITE MEASUREMENT

cEXCLUDESPC does not include Overheads, Contingencies, etc. Eg. Earthwork in Excavation

EUse Knowledge about PC helps to improve designs, processes and parts so that profitability can be increased for the same sale price or even at lesser prices Though the Pit or Trench can be taken off accurately from the foundation drawings, still the actual earthwork volume will vary due to presence of Roots, Boulders, etc. which foul across the excavation work and therefore require to be pulled out leading to INCREASED quantities Only site measurements can help to quantify the work

fIn civil engg construction contracts, PC is the amount of money say a few thousands of rupees or say a few lakhs of rupees kept aside for purchasing various items which are listed in the initial BoM but NOT Specified NOT described NOT Rated NOT quantified All specifications, rating, quantification, etc. done only later Though the work quantities are not known in the beginning, however the rates are fixed in the initial stage itself.

gEg** Sanitaryware ** Tiles ** Modular Kitchen ** Paints ** Air Conditioning Ducts ** Plumbing and Sanitaryware ** Interiors and Finishes for different work cabins in an office ** the type of Machine Foundation Pedestal for a particular machine in a factory ( the type of machine itself is still not specified in the beginning when the factory floor is designed )

hPayment Contractor is paid the ACTUALS for purchase of these PC itemsFor installing or fixing or executing these work items under PC, the rates for execution alone are already QUOTED by Contractor and Agreed To upon by the Client in the beginning itself Eg. Rate for Painting -- Rs XX per sq. ft for 2 coats Mentioned in the initial estimates / bids / quotations But rate of paint material not quoted It is marked as PC The client earmarks some amount towards Purchase of Paint Client allows actual payment to the main contractor or to the specialist sub-contractor engaged by the main contractor or engaged directly

7Differentiate between Estimate and Actual Cost

#Parameter Estimate Cost Actual Cost

APreparing stage Prepared before the beginning of the workPrepared at the end of the work

BConcept Based on the Drawings, Specifications, Past Experience and some predictions Based on the actual bills, and other payments made based on the actual field measurements

CAccuracy Prone to variations and deviations due to unavoidable changes in the work Very less error -- Errors too will be due to willful negligence, or due to unnoticed omissionsor unavoidable situations where measurements could not be taken

8Differentiate between Prime Cost & Capital Cost

#Prime Cost Capital Cost

aDEfn Prime Cost PC is the basic cost to be spent / paid for buying or manufacturing a given item Capital Cost is the TOTAL COST of all works and all costs Incurred from the beginning of the project and upto Mandatory Maintenance and Guarantee Period

bINCLUDESIn manufacturing, PC refers to the total direct costs towards raw materials, labour, packaging. transporting, etc. The Capital Cost includes all Direct Costs, Indirect Costs, Contingencies, Overheads and all other costs related to the comprehensive completion of the project

cEXCLUDESPC does not include Overheads, Contingencies, etc. CC includes Overheads, Contingencies, and every other cost

EUse Knowledge about PC helps to improve designs, processes and parts so that profitability can be increased for the same sale price or even at lesser prices Capital Cost > Prime Cost

fIn civil engg construction contracts, PC is the amount of money say a few thousands of rupees or say a few lakhs of rupees kep