Reliance data in EPC contracts
The starting point of many engineering procurement and construction (EPC) tenders and contract negotiations is as follows: the owner/employer provides the contractor with the data they have in their possession regarding the project together with a specific statement that 'the employer does not give any warranty as to the completeness, accuracy or fitness for purpose' of that information.
They do this to avoid any claim by the contractor during the project execution on the basis that the provided information is inaccurate or incorrect. Sometimes the situation is even worse and the owner/employer simply tries to avoid giving any information.
In practice, withholding information is counterproductive as it does not enable the EPC contractor to quote properly, with reasonable efforts. Contractors may walk away from the tender, overprice or underestimate the project’s cost. In the latter case, contractors often create trouble during the execution phase in an attempt to limit their losses.
FIDIC 1999 Silver Book (Clause 5.1) requires the contractor to scrutinise the employer’s requirements prior to the bid submittal. The employer shall not be responsible for any error, inaccuracy or omission of any kind in the employer’s requirements except for data and information which are stated as immutable or the responsibility of the employer and also except for data and information which cannot be verified by the contractor. Having some data on which the contractor may rely (reliance data) is therefore good industry practice and in line with the contract standards.
The difficulty starts when identifying precisely the 'reliance data', 'baseline data' or whatever word is defined in the contract to introduce the same concept. The data is usually parked in an appendix containing a limited list of data for which the employer takes responsibility. An objective methodology to establish 'reliance data' is to look at the project (to be executed) as a 'black box':
- Whatever is in the box are the works to be executed. These are defined in a functional, not detailed, not prescriptive specification. The reliance data should not include any information from within the project 'black box'.
- The project 'black box' is somehow connected to, and interacting with, its surroundings/environment. It is physically attached to/founded on the outside world. It also receives some inflow. The 'black box' can be impacted/shaken-up by the outside environment. The quality, magnitude and characteristics of these foundations, inflows, connections and impacts are data that can, and often should, become reliance data.
In case of building a hydro power plant for example, the following can be reliance data:
- Geo-technical baseline data: reference characteristics of subsurface conditions like rock classes ('foundations').
- Water quality: chemical composition of water quality for which the penstocks and turbine equipment should be designed; maximum water temperature to be taken into consideration for the design of the cooling system; hydrological data ('inflow').
- Grid connection information: data related to the transmission line and grid characteristics (voltage, frequency). The electric grid often still has to be expanded under a separate contract ('connections').
- Maximum wind speed or seismic acceleration coefficient: design requirements that the 'black box' will have to withstand ('impacts').
Some concept of reliance data is healthy for a balanced EPC contract. It is necessary to minimise the information to those design inputs that are essential and cannot reasonably be verified by the contractor during the tender stage. This includes information that is the result of long-term data series or unaccessible or needing unreasonable efforts and resources to obtain during the tender stage (when the contractor is not sure to be awarded the contract).
--JFJ Afitac 18:29, 03 Jun 2018 (BST)
[edit] Related articles on Designing Buildings
Featured articles and news
What they are, how they work and why they are popular in many countries.
Plastic, recycling and its symbol
Student competition winning, M.C.Esher inspired Möbius strip design symbolising continuity within a finite entity.
Do you take the lead in a circular construction economy?
Help us develop and expand this wiki as a resource for academia and industry alike.
Warm Homes Plan Workforce Taskforce
Risks of undermining UK’s energy transition due to lack of electrotechnical industry representation, says ECA.
Cost Optimal Domestic Electrification CODE
Modelling retrofits only on costs that directly impact the consumer: upfront cost of equipment, energy costs and maintenance costs.
The Warm Homes Plan details released
What's new and what is not, with industry reactions.
Could AI and VR cause an increase the value of heritage?
The Orange book: 2026 Amendment 4 to BS 7671:2018
ECA welcomes IET and BSI content sign off.
How neural technologies could transform the design future
Enhancing legacy parametric engines, offering novel ways to explore solutions and generate geometry.
Key AI related terms to be aware of
With explanations from the UK government and other bodies.
From QS to further education teacher
Applying real world skills with the next generation.
A guide on how children can use LEGO to mirror real engineering processes.
Data infrastructure for next-generation materials science
Research Data Express to automate data processing and create AI-ready datasets for materials research.
Wired for the Future with ECA; powering skills and progress
ECA South Wales Business Day 2025, a day to remember.
AI for the conservation professional
A level of sophistication previously reserved for science fiction.
Biomass harvested in cycles of less than ten years.
An interview with the new CIAT President
Usman Yaqub BSc (Hons) PCIAT MFPWS.
Cost benefit model report of building safety regime in Wales
Proposed policy option costs for design and construction stage of the new building safety regime in Wales.
Do you receive our free biweekly newsletter?
If not you can sign up to receive it in your mailbox here.
























