The six sections
| Section | Content | Part of the contract |
|---|---|---|
| 0 | Guidance for preparing the specification | no |
| 1 | Scope | yes |
| 2 | Materials and components | yes |
| 3 | Execution | yes |
| 4 | Incidental and additional services | yes |
| 5 | Measurement and final account | yes |
The third column contains the most frequently overlooked point in this standard. It separates the part that becomes contract content from the part that does not.
Section 0 addresses whoever is tendering
Section 0 contains guidance for preparing the specification. That guidance does not become part of the contract. It is not an obligation towards the contractor but instruction for whoever is tendering.
Observing it is nonetheless a precondition for a proper specification within the meaning of the VOB/A. The section lists which particulars are to be included in the specification as the individual case requires, such as the condition of the site, existing installations, access routes and their restrictions, or regulatory requirements.
A clear division of roles follows for practice. One part addresses whoever is tendering, the other both parties to the contract.
| Part | Role | Effect |
|---|---|---|
| Section 0 | the checklist of whoever is tendering | every particular named there and missing from the bill is a gap that returns as a variation |
| Sections 1 to 5 | the contract content | they apply between the parties without needing to be repeated in the contract |
Section 4: what is included in the price
This is the section with the greatest economic effect, and it rests on a simple distinction. It decides what is owed without a separate item.
| Term | Status | Payment |
|---|---|---|
| Incidental services | form part of the contractual work even without mention in the contract | covered by the prices of the work items |
| Additional services | do not form part of the contractual work unless expressly agreed | tendered and paid separately |
Incidental services under DIN 18299 include setting up and clearing the site including plant, protection and safety measures under accident prevention rules, and further work securing proper progress. The full list appears in section 4.1 of the standard.
A rule follows for pricing that separates a sound tender from an assailable one: what counts as an incidental service must be priced by the tenderer even where the bill of quantities does not say so. Anyone unaware of these services prices too low and bears the result.
Conversely for whoever is tendering: what counts as an additional service belongs in its own item. Otherwise a variation arises, at a point when no competition exists.
Section 5: measurement
Section 5 governs how measurement proceeds. It contains the general deduction rules, applying so far as the trade-specific ATV provides nothing to the contrary.
Two examples show the system. Where measurement is by area, built-in special units are measured over, that is included rather than deducted. Where a recess extends partly into adjoining areas measured separately, the proportionate recess area is used to determine the amount measured over.
The rules are detailed and substantial in effect: two measurements of the same element diverge where deductions are handled differently. The account follows the ATV. The article on the deduction rules covers them in detail.
Precedence against the trade-specific ATV
DIN 18299 applies to all construction work, but it does not apply in priority. Divergent provisions in ATV DIN 18300 onwards take precedence.
A checking sequence follows that applies to every measurement question. It begins with the trade and ends with the general rule.
- Consult the trade-specific ATV. Where it provides for the question, that provision governs.
- Only where it is silent, fall back on DIN 18299.
- Where no ATV exists for the trade, DIN 18299 applies directly.
The third case is commoner than assumed, because not every construction service has its own standard. DIN 18299 expressly fills that gap.
The opening for digital methods
With the 2019 edition, DIN 18299 was opened to model-based methods in a first step. A general enabling clause was introduced in sections 0 and 5, permitting digital measurement methods.
Two points bear noting. First, application presupposes agreement; without it the rules of section 5 apply unchanged. Second, the opening concerns the method of quantity take-off, not the deduction rules themselves: a quantity derived from a model is the quantity contractually owed only where the model reflects the rules of the ATV.
For tendering it follows that the measurement method belongs named in the preliminaries where it is to depart from the default. Absent that naming, the rule of the standard applies.
Sections 2 and 3 in practice
Two sections receive less attention when pricing yet act directly on price. Both move work into the unit rate without an item existing for it.
| Section | Subject | Effect on the price |
|---|---|---|
| Section 2, materials and components | the works also comprise supplying the associated materials and components, including unloading and storing on site | anyone pricing an item prices supply and storage with it, without that appearing in the text |
| Section 3, execution | the duty to observe the rules of the responsible authorities where traffic, supply and disposal installations lie within the site | where their position is not stated it must be investigated, and that investigation is an additional service |
The last point is a model case of the system: the duty exists, but performing it is separately payable where the tendering party could not state the position. Omitting that particular therefore moves an item out of competition and into a variation.
What belongs in the preliminaries
Section 0 names a form of words to be included in the preliminaries to the bill of quantities: where the specification refers to technical specifications, equivalent specifications count as admitted even without the express addition to that effect. It applies even without the express addition.
The clause has a procurement law purpose and prevents impermissible product specification. It belongs in every bill of quantities, and its absence is a procurement defect open to challenge.
The structure of the preliminaries is covered in the article on building a bill of quantities. It also sets out which particulars must appear there.
Related articles
This article reflects the position of the standards at the date of checking and serves professional orientation. It does not constitute legal advice and does not replace assessment of the individual case.