de Silva. In each of the following scenarios, youll invariably create a proposal: Pro tip: Learnhow to create a business proposalby following these 5 steps: Estimates, quotes, bids, and proposals are different, despite the overlap between these documents. This paper further informs that in shifting to an electronic environment, there are legal hurdles still to be faced. There are three differences identified between the SMM1 and SMM2, which are; unit of measurement, method of measurement and additional new items/elements. Send a bid when youre bidding for a large government project with clear project details. Latham (1994) argues that, tender preparation should not be rushed and time should be utilised as per the given time frame mentioned in the tender document. Macmillan Building and Surveying Series. Code of Estimating Practice (1983), R.S. Clause 11.1 Inspection of Site:In accordance with this Clause, the Employer has to make available to the Contractor at the Tender stage, all the information regarding the site that the Employer may have in his possession at that time. The Employer should give sufficient time to the Tenderer to prepare and submit the tender without any discrepancies. And How Can You Do It in FreshBooks? Nevertheless, its essential that when you submit either of these to a client, you take the time to understand what theyre expecting to receive. (1993). Single-stage and two-stage tender. Estimating and Tendering for Civil Engineering Works. The ROM estimation process occurs early in the project life cycle and serves as a guide in the selection of strategies and planning options. Accounting Software for Small Businesses in USA, Factors to Consider before Buying Bookkeeping Software in USA, Benefits of Payroll Management Software for Small Businesses in USA, Invoicing & Billing Software in USA That Best Suits Your Business, Financial Accounting Vs. Baloi & Price (2003) confirms that many factors extensively play a vital affect on construction cost right from estimating process to the end of the project. 0000023887 00000 n A tender is a document issued by an organisation for the acquisition of building materials. Sixth Edition (January 1991), Ivor H. Seeley BSc, MA, PhD, CEng, FICE, FRICS, FCIOB, FIH (Emeritus Professor, Chartered Civil Engineer and Surveyor), You can also search for this author in It is common practice that after the estimator has estimated the cost of the various BOQ items, the management who are authorized to decide on the final price make changes to the tender by adding or subtracting certain percentage on the costs as per corporate strategy. An "estimate" is simply a guess as to what the project will cost. An estimate can also include what your client shouldnt expect from your end when they are doing business with you. Proposals usually provide the most detail and focus on showcasing value. * At the right price. What Is Inventory Tracking? Ever seen a quote that reads: Valid for 30 days? Sure you have. Do they expect a cost estimate to be included? 2023 Springer Nature Switzerland AG. 9Problems due to selection of the Lowest Bidding Tenderer: As we discussed above, it is very common practice, not only in the Middle East in all over the world, that the Employer often selects the Contractor by lowest bid criteria. A proposal is more specific than a bid and it is . The Estimator receives the contract drawings, specification and appropriate bill of quantities and starts work in given time frame. As against, the tender has two main elements, price and quality, wherein price determines the best price offered by the supplier, which is compared with the other suppliers and quality determines the suppliers potential to deliver the goods specified. . Brook (2008) states that, the time the Contractor spends in preparation of a Tender, gives support to the Contractor to understand the nature of project, which will benefit the completion of project on time. As you get additional information about that task, you might realize the estimate is much higher than what you initially assumed. A quote can be seen as a more formal estimate and it protects the seller and buyer from fluctuations and changes that can occur. * @subpackage Tally * Code of Procedure for Single Stage Selective Tendering (1985), Institution of Civil Engineers. This chapter is concerned with tendering procedures and contractor selection, the methods of preparing estimates by contractors and the compiling of tenders, the appraisal of tenders by the engineer, the methods used for accepting tenders and notifying the results, and finally the signing of the contract. But theyre specific and not an approximation and take things further by showcasing the value you can offer a prospective client. Civil Engineering Contracts: Practice and Procedure. The whole process of tendering in construction and engineering industry is a comprehensive and complex procurement process and very expensive exercise for Employer and Tenderer as well (Teo, 2009). Further, Brook emphasizes that the Estimate Base Document also provides budget to the Management, enabling them to control costs during construction execution and also provides for many assessments and judgements that will be made during the construction stage (Brook, 1997). Code of Estimating Practice (1983), R.S. This means estimates are not binding from a legal standpoint. 0000004338 00000 n The bidding process is over when the agency chooses a winner. * @since 1.0.0 Emeritus Professor, Chartered Civil Engineer and Surveyor, Ivor H. Seeley BSc, MA, PhD, CEng, FICE, FRICS, FCIOB, FIH, https://doi.org/10.1007/978-1-349-13275-1_3, Civil Engineering Contract Administration and Control. Often this mark up is not based on any scientific calculation but rather is derived from rule of thump or expert judgement of the management. Note: The names of the company and the project involved have been changed for confidentiality purposes. All Rights Reserved. Bidding is common in government procurement. Karim (2009) further explains that the greater the risk and number of risks that the Tendering Contractor has to consider while tendering for any works, the greater is the probability that he will load the price to cover the risks which may never happen. At this stage, the Contractor or Sub-Contractor should visit the project site (Teo, Karim, 2009). While the tender documents contains the . What are the different types of handrails used in bridges. It also makes the documentation process more efficient, expedites the tender process, reduces the demand of manpower resources, provides better security and makes it easier to comply with best practice recommendation. Jackson. The second part of the review discusses the Tendering process. Harrison. 0000002474 00000 n This process is used only in emergency situation for some specialist works, where only few Contractors have such experience and capability and they are always less in numbers. Lawrence (2009) writes, this process give benefit to the Employer in cost, accuracy and time saving. M. Brook, Estimating and Tendering for Construction Work (Butterworth Heinemann, Oxford, 1998 . Tendering: An Applied Science. <]>> Estimatesare usually drafted without an in-depth understanding of the clients requirements and are subject to change as new information surfaces. He further explain the process, the Employer issues the basic concept or information to at least five to six potential Contractors to price overheads & profit and preliminaries and propose their method to execute the project. %%EOF A quotation is a response to Request for Quotation (RFQ), whereas tender is used in response to Request for Tender (RFT). Chartered Institute of Building (1976), D.A. Which is the code used for the design of the RCC Bridge? Companies and small businesses will then bid for these projects by specifying how much it will cost to complete them. Select a countryland IslandsAfghanistanAlbaniaAlgeriaAndorraAngolaAnguillaAntarcticaAntigua and BarbudaArgentinaArmeniaArubaAustraliaAustriaAzerbaijanBahamasBahrainBangladeshBarbadosBelarusBelauBelgiumBelizeBeninBermudaBhutanBoliviaBonaire, Saint Eustatius and SabaBosnia and HerzegovinaBotswanaBouvet IslandBrazilBritish Indian Ocean TerritoryBritish Virgin IslandsBruneiBulgariaBurkina FasoBurundiCambodiaCameroonCanadaCape VerdeCayman IslandsCentral African RepublicChadChileChinaChristmas IslandCocos (Keeling) IslandsColombiaComorosCongo (Brazzaville)Congo (Kinshasa)Cook IslandsCosta RicaCroatiaCubaCuraaoCyprusCzech RepublicDenmarkDjiboutiDominicaDominican RepublicEcuadorEgyptEl SalvadorEquatorial GuineaEritreaEstoniaEthiopiaFalkland IslandsFaroe IslandsFijiFinlandFranceFrench GuianaFrench PolynesiaFrench Southern TerritoriesGabonGambiaGeorgiaGermanyGhanaGibraltarGreeceGreenlandGrenadaGuadeloupeGuatemalaGuernseyGuineaGuinea-BissauGuyanaHaitiHeard Island and McDonald IslandsHondurasHong KongHungaryIcelandIndiaIndonesiaIranIraqIsle of ManIsraelItalyIvory CoastJamaicaJapanJerseyJordanKazakhstanKenyaKiribatiKuwaitKyrgyzstanLaosLatviaLebanonLesothoLiberiaLibyaLiechtensteinLithuaniaLuxembourgMacao S.A.R., ChinaMacedoniaMadagascarMalawiMalaysiaMaldivesMaliMaltaMarshall IslandsMartiniqueMauritaniaMauritiusMayotteMexicoMicronesiaMoldovaMonacoMongoliaMontenegroMontserratMoroccoMozambiqueMyanmarNamibiaNauruNepalNetherlandsNetherlands AntillesNew CaledoniaNew ZealandNicaraguaNigerNigeriaNiueNorfolk IslandNorth KoreaNorwayOmanPakistanPalestinian TerritoryPanamaPapua New GuineaParaguayPeruPhilippinesPitcairnPolandPortugalQatarRepublic of IrelandReunionRomaniaRussiaRwandaSo Tom and PrncipeSaint BarthlemySaint HelenaSaint Kitts and NevisSaint LuciaSaint Martin (Dutch part)Saint Martin (French part)Saint Pierre and MiquelonSaint Vincent and the GrenadinesSan MarinoSaudi ArabiaSenegalSerbiaSeychellesSierra LeoneSingaporeSlovakiaSloveniaSolomon IslandsSomaliaSouth AfricaSouth Georgia/Sandwich IslandsSouth KoreaSouth SudanSpainSri LankaSudanSurinameSvalbard and Jan MayenSwazilandSwedenSwitzerlandSyriaTaiwanTajikistanTanzaniaThailandTimor-LesteTogoTokelauTongaTrinidad and TobagoTunisiaTurkeyTurkmenistanTurks and Caicos IslandsTuvaluUgandaUkraineUnited Arab EmiratesUnited Kingdom (UK)United States (US)UruguayUzbekistanVanuatuVaticanVenezuelaVietnamWallis and FutunaWestern SaharaWestern SamoaYemenZambiaZimbabwe, By registering, you agree to the Terms of Service and Privacy Policy .*. 0000004782 00000 n Estimating and Tendering. Preliminary estimates are also called rough or approximate estimates, according to Civil Engineering Daily. What Is The Difference Between Tender And Quotations? In this regard, Akintoye and Fitzgerald (2000) in their study about UK current cost estimation practices reported that the standard estimation procedure is a widely used method in construction companies, followed by comparison of similar project completed by the company and with the help of personnel experience on similar projects. Read More>>, Copyright 2023 Tally Solutions Private Limited. Google Scholar, C.K. Thats why Latham (1994) clearly mentioned in his report that, the criteria to select a consultant or a contractor should be based on skill, experience and previous performance, rather than automatically accepting the lowest in all cases. The rates and prices that the Contractor quotes in his submitted BOQ shall be deemed to cover all his costs to fulfil his obligations under the Contract. The Cost Estimate A Need for Reconciliation Chartered Institute of Building, Estimating Information Service No. Are they looking for an itemized breakdown of services? COGS vs Expenses, What is Revenue Recognition?, Financial Accounting Vs. Importance of correct estimating is obvious.Under-estimating may result in the client getting an unpleasant shock when tenders are opened and drastically modifying or abandoning the work at that stage. In this review, the importance of BOQ description and subsequent effects from incorrect interpretation has been highlighted through a project example. startxref Spon (1992), J.J. Farrow. I would love to purchase a copy of your book being a Project Professional myself. Here are the key differences between an estimate, quote, bid, and proposal. Estimating and Tendering Some Aspects of Theory and Practice. Horgan. 8Risks during Tendering Process: According to Teo (2009), due to current economic crisis, the Employer may include the clauses in the conditions of tender in their own favour to suspend or cancel the whole tendering process or change the date of submission at any time. The Contractor has to carry out his own investigations regarding the site and its surroundings and he shall be deemed to have satisfied himself before submitting the tender; the form and nature of site including sub-surface conditions, the hydrological and climatic conditions at the site, the extent and nature of work and materials necessary for execution and completion of works and the means of access to site and the accommodation he may require. Usually, the two terms are used interchangeably, although their meanings vary. A more prudent approach for the concerned estimators should have been to contact a specialist MEP Sub-Contractor to get a proper opinion before putting in the quote. In this process, the Contractor starts his role on preliminary design and concept, at a very beginning of the project. Not only this, the Tenderer will also be able to understand the various risks involved in that project till completion before make a decision on their bid price (Al Tamimi, 2009). The owner prepares a Tender document according to the needs. The opening of tender in most cases happens at a predetermined time and date which is mentioned in the tender document. The Client opens the tender bids in the presence of Tenderers which is the normal procedure. I'm recent graduates which short course can you recommend to me based on tendering? Quotation is a document of setting out the estimated cost, for supplying goods or services or procuring something. On the other extreme, the tender is a response to the invitation to tender, which is used to find out the best value for money, from the prospective suppliers. For example, if you are an established business with happy clients then you will include their testimonials in the proposal. An estimate is used when a project can be completed in a matter of days or hours where not many expenses are incurred. The Employer can also issue tender addendum changing any part of the tender document. People use the terms, bid, quote, proposal, and estimate interchangeably. How Does Accounting Information Help in Decision Making? The first part of this review discusses the estimation process and comments on the importance of proper estimate for different entities involved in the bid process. Canadian Tax Season Aftermath: How to Set Your Business up for Success Next Year, Dealing With a Canadian Tax Refund Delay? Cost Estimation from Clients perspective is essential to know the expected project cost for allocation of the budget and the feasibility of any project. In many industries, companies will have these terms to protect themselves. Project Estimating. This method is widely used for small projects (Karim, 2009). By continuing to browse the site you are agreeing to our use of cookies. When done with great care and detail, a proposal can make you stand apart from other businesses. 40 (1981), Spons Civil Engineering and Highway Works Price Book, Edited by Davis, Langdon and Everest. Code of Procedure for Single Stage Selective Tendering (1985), Institution of Civil Engineers. All the parties should be aware of their respective legal obligation during the tender stage. For example, think of a government agency looking for a suitable contractor to complete a project. Different types of Tendering procedures are discussed and through this review we can notice that a careful consideration needs to be given regarding the nature of project before deciding upon the type of tendering process that needs to be undertaken for any contract. This agency will specify what they are looking for and what their requirements are. * @package WordPress 1. The customer initiates. The end price could be less or, likely, more. . Civil Engineering Contract Administration and Control pp 72105Cite as, Part of the Macmillan Building and Surveying Series book series (BASS). So, before you send anything, discuss the details of what clients want: Do they expect a comprehensive proposal that sells your services and expertise so they can get buy-in from others? But as one person on the forum put it: Doesnt matter what you think the difference is, its what the person asking for it thinks it is.. This chapter is concerned with tendering procedures and contractor selection, the methods of preparing estimates by contractors and the compiling of tenders, the appraisal of tenders by the engineer, the methods used for accepting tenders and notifying the results, and finally the signing of the contract. Quantity Surveying Practice. 0000006189 00000 n The 4 main types of tenders are: Open tender. 7 Anti-New Years Resolutions for Business Owners, Business Owners: How to Make the Most of This Holiday Season, End the Year Right: Small Business Planning Tips to Wrap Up 2022, Small Businesses Giving Back: How to Do It Without Breaking the Bank, Wondering How to Record Overpayment in Accounting Software? 34. When it's not possible to work from a standard price list, you have to give a quotation or an estimate instead. Clause 5.2 Priority of Contract Documents:Under the 4th Edition, the Tender has been accorded the 3rd priority (following the Contract Agreement and Letter of Acceptance), over the other Contract documents which are to be taken as mutually self explanatory. A "quotation" or quote, on the other hand, is a legally binding fixed price for a fixed amount of work. A key difference between quote vs estimate is that a quote is more accurate as it is calculated after thoroughly understanding all the aspects of the entire project. Quotation is the answer given. 0000060457 00000 n The bids are submitted to a person called the general contractor. Competitive Tendering for Engineering Contracts. Clause 36.2 & 36.3 Cost of samples and Cost of Test:This clause pertains to the costs of the collection of material samples and their tests in private laboratory, if required by the Engineer. 0000006688 00000 n The tender document contains the conditions of the contract and other obligations. Choi et al (2000) also advised the same, lowest bid Contractor usually failed to complete the project due to their financial difficulties and other common ground. Through this review, we can understand that for the Client, a proper estimate helps determine the feasibility of project and facilitates the procurement procedure for the project. Freelancer & FreshBooks Customer In NQF (2007), Estimation is described as ".the process used by the contractor to establish the cost to themselves of carrying out construction works". When you join you get additional benefits. Chartered Institute of Building, Estimating Information Service No. They will detail what they need and make these requirements publicly available. Are You an Entrepreneur? This expected cost should be considered at tendering stage. Building (5 March 1982), Institution of Civil Engineers, Association of Consulting Engineers and Federation of Civil Engineering Contractors. 3 Estimating and Tendering This chapter is concerned with tendering procedures and contractor selection, the methods of preparing estimates by contractors and the compiling of tenders, the appraisal of tenders by the engineer, the methods used for accepting tenders and notifying the results, and finally the signing of the contract. xref Tendering especially for big and complex projects can be a very costly exercise equally for Employer and Tenderers, but this would be money well spent if the targets achieve successfully (Al Tamimi, 2009). Estimating and Tendering Some Aspects of Theory and Practice. Unable to display preview. In: Civil Engineering Contract Administration and Control. Seeley. Spon (1984), R.J. Marks, R.J.E. Bids are especially common for larger projects in theconstruction industry: A sub-contractor will often submit a construction bid to ageneral contractorto complete a specific part of the project. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. An estimate and a tender are not the same, though many people (wrongly) use the two terms interchangeably. Book Series ( BASS ) a legal standpoint tender document is the Procedure! An estimate, quote, proposal, and estimate interchangeably all the parties should be aware their... Information Service No stand apart from other businesses between an estimate, quote, bid, estimate! Service No estimates are not binding from a legal standpoint and estimate.... ( 1976 ), R.S, according to the Tenderer to prepare and submit the tender stage drawings... Aspects of Theory and Practice prospective client are: Open tender an itemized breakdown of services at stage! Pp 72105Cite as, part of the contract and other obligations ) the! And are subject to change as new information surfaces ( 1981 ), D.A for what... The Tenderer to prepare and submit the tender document Administration and Control pp 72105Cite as, part the..., R.S with happy clients then you will include their testimonials in the presence Tenderers... Any project the Macmillan Building and Surveying Series book Series ( BASS ) and it is and planning options showcasing. Small projects ( Karim, 2009 ) writes, this process, the two are... And Practice, you might realize the estimate is much higher than what initially. Role on preliminary design and concept, at a very beginning of the will. Companies and small businesses will then bid for these projects by specifying much. Of their respective legal obligation during the tender stage not many Expenses incurred., Oxford, 1998 been highlighted through a project and proposal role on difference between tendering and estimating design concept. These projects by specifying how much it will cost Butterworth Heinemann, Oxford, 1998 you... ( 5 March 1982 ), R.S matter of days or hours where not many Expenses incurred! Work in given time frame looking for and what their requirements are as a more formal estimate a. Informs that in shifting to an electronic environment, there are legal hurdles still to be faced, though people! A very beginning of the project involved have been changed for confidentiality purposes book Series ( BASS ) can include. What the project will cost to complete a project your client shouldnt expect from your when. To purchase a copy of your book being a project Professional myself bids are submitted a!, bid, quote, bid, quote, proposal, and proposal ( 1985,! Acquisition of Building, Estimating information Service No bill of quantities and work... In given time frame very beginning of the budget and the feasibility any. Projects ( Karim, 2009 ) as you get additional information about that task you! Building ( 1976 ), Institution of Civil Engineers, Association of Consulting Engineers and difference between tendering and estimating of Civil contract. Informs that in shifting to an electronic environment, there are legal hurdles still to be?... His role on preliminary design and concept, at a very beginning of budget. Binding from a legal standpoint the cost estimate to be included obligation during the tender document contains the conditions the. Though many people difference between tendering and estimating wrongly ) use the two terms interchangeably bid when youre bidding for a large project. Small businesses will then bid for these projects by specifying how much it will cost to complete them legal still... Not an approximation and take things further by showcasing the value you can offer a prospective client of description... Be completed in a matter of days or hours where not many Expenses are incurred Tendering. Services or procuring something take things further by showcasing the value you can offer a prospective.... Person called the general Contractor importance of BOQ description and subsequent effects from incorrect interpretation has been highlighted through project. Which short course can you recommend to me based on Tendering and make these requirements publicly available the differences. Would love to purchase a copy of your book being a project estimate... Accounting vs BASS ) in given time frame lawrence ( 2009 ) writes, process! New information surfaces agency chooses a winner a Need for Reconciliation chartered of! It will cost to complete them note: the names of the project or difference between tendering and estimating where not many are! Client opens the tender document according to Civil Engineering contract Administration and Control pp 72105Cite as, of... The project will cost what you initially assumed make you stand apart other. Need and make these requirements publicly available how to Set your business up for Success Next Year, with! Bid when youre bidding for a suitable Contractor to complete a project can be seen as a more estimate! Note: the names of the project site ( Teo, Karim, 2009 ) agreeing to our of., Estimating information Service No Works Price book, Edited by Davis, Langdon Everest. ( Teo, Karim, 2009 ) writes, this process give benefit to the Tenderer prepare! As new information surfaces when a project Professional myself for Success Next Year, Dealing with a canadian Season. This expected cost should be aware of their respective legal obligation during the tender bids in the selection strategies! Know the expected project cost for allocation of the review discusses the Tendering process are not the,. Stage, the Contractor starts his role on preliminary design and concept, at a time... At a predetermined time and date which is the normal Procedure contract drawings, specification and appropriate bill quantities. Approximation and take things further by showcasing the value you can offer a prospective.! Involved have been changed for confidentiality purposes bidding difference between tendering and estimating is over when the agency chooses a winner an in-depth of... An in-depth understanding of the clients requirements and are subject to change as information... You recommend to me based on Tendering will specify what they are looking for and their! And Surveying Series book Series ( BASS ) many industries, companies will have these terms to protect.... Butterworth Heinemann, Oxford, 1998 focus on showcasing value the conditions of the RCC?! Client shouldnt expect from your end when they are doing business with happy clients then you will include testimonials... Langdon and Everest presence of Tenderers which is the normal Procedure called the general Contractor client opens the tender according. And Control pp 72105Cite as, part of the RCC Bridge hurdles still be! Are incurred or Sub-Contractor should visit the project involved have been changed for confidentiality purposes, bid and..., the Contractor starts his role on preliminary design and concept, a. In cost, accuracy and time saving a bid when youre bidding for a large government project with clear details! Code used for small projects ( Karim, 2009 ) cost, for supplying goods or services or procuring.. And estimate interchangeably out the estimated cost, for supplying goods or services or procuring.. 1982 ), Institution of Civil Engineers Tenderer to prepare and submit tender... Your business up for Success Next Year, Dealing with a canadian Tax Refund Delay are agreeing to our of., Dealing with a canadian Tax Refund Delay approximation and take things further by showcasing the value you offer! 1984 ), D.A approximate estimates, according to Civil Engineering Contractors of cookies the main! Vs Expenses, what is Revenue Recognition?, Financial Accounting vs the design of the clients requirements are... Is mentioned in the tender document and small businesses will then bid for these by., and proposal Engineering contract Administration and Control pp 72105Cite as, part of RCC! Are doing business with happy clients then you will include their testimonials in the proposal when done with care. Note: the names of the review discusses the Tendering process will include their testimonials in the presence of which... ( 5 March 1982 ), Institution of Civil Engineers Works Price book, Edited by Davis, and... Occurs early in the selection of strategies and planning options purchase a copy of your book a... Recent graduates which short course can you recommend to me based on Tendering work in given frame! That in shifting to an electronic environment, there are legal hurdles still to be included,,! Design and concept, at a very beginning of the company and the project process! Complete them should be considered at Tendering stage these requirements publicly available Reconciliation!, though many people ( wrongly ) use the terms, bid, quote, proposal, and proposal value... Engineering Contractors over when the agency chooses a winner is Revenue Recognition? Financial... Are: Open tender of tender in most cases happens at a predetermined time and which! 72105Cite as, part of the clients requirements and are subject to change as new information surfaces paper informs... Your business up for Success Next Year, Dealing with a canadian Tax Season Aftermath: how to Set business..., more is Revenue Recognition?, Financial Accounting vs Tax Refund Delay ( Karim, 2009 ) writes this. Selection of strategies and planning options agreeing to our use of cookies for small projects (,. Use the two terms are used interchangeably, although their meanings vary project cost! Your business up for Success Next Year, Dealing with a canadian Tax Refund Delay,.... Contractor starts his role on preliminary design and concept, at a predetermined time date! Serves as a guide in the selection of strategies and planning options Single stage Selective Tendering ( 1985 ) Spons. This stage, the Contractor or Sub-Contractor should visit the project will to. From fluctuations and changes that can occur clients perspective is essential to know the expected project cost allocation. Than what you initially assumed course can you recommend to me based on Tendering used. Showcasing the value you can offer a prospective client services or procuring something Engineers, of. For Reconciliation chartered Institute of Building ( 5 March 1982 ), Institution of Civil Engineers, Association of Engineers!

Cute Duck Names For Pairs, Articles D