Contractor’s Operations on Site – Key Differences Between FIDIC 1999 vs 2017 Explained

1️⃣ Purpose of Clause 4.23 / Clause 4.22

Let’s start by asking: Why does this clause exist in the first place?

Picture a construction site — materials everywhere, equipment humming, people in high-vis gear moving about. Now imagine this activity creeping outside the site boundaries, or worse, leaving behind a trail of waste, rubble, or even hazardous materials. This clause is here to prevent exactly that scenario.

✨ What’s the clause trying to achieve?

✅ It tells the Contractor: “Hey, keep your work, people, and machines inside the boundaries we’ve agreed on.”
✅ It tells the Employer: “Don’t worry, the Contractor will clean up and leave the site in good shape.”
✅ It sets the stage for a professional, safe, and respectful use of the project site.

In the 1999 edition, the clause was already effective — it required the Contractor to stay within the Site, clean up after themselves, and only keep what’s necessary for outstanding work.

But the 2017 edition took things up a notch. Why? Because the world changed. Environmental awareness increased, health and safety regulations tightened, and project complexity grew.

So FIDIC responded with:

• 🌱 A clear environmental tone — now the clause explicitly includes “hazardous waste.”
• 🛑 Engineer oversight — the Engineer must agree where leftover Goods can be kept during the Defects Notification Period.

The intention is the same — protect the site and the Employer’s interests — but the 2017 update is more robust and aligned with today’s industry expectations.

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🔍 Key Differences: 1999 vs 2017 (Tabular Overview)

Feature	1999 Edition (Clause 4.23)	2017 Edition (Clause 4.22)
Site Boundaries	Contractor to confine all activities to the Site.	Same requirement, but with added emphasis on “additional areas” approved by Engineer.
Waste Removal	Rubbish, debris, Temporary Works must be removed.	Same, plus hazardous waste is explicitly included.
Retained Goods Post-Taking-Over	Contractor can retain necessary Goods during DNP.	Contractor can retain Goods only in Engineer-approved areas.
Cleanliness Obligation	Implied through removal duties.	Strengthened: Site must be free of obstruction “at all times.”
Engineer’s Role	Not explicitly required for post-Taking-Over storage.	Requires Engineer’s agreement for retained Goods’ location.

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2️⃣ Breakdown of the Clause

Let’s zoom into the wording and unpack it.

3️⃣ Key Interpretations and Implications

Let’s translate the dry legalese into practical, everyday consequences.

✅ Contractor’s Responsibilities

• Maintain strict site boundaries — no unauthorized expansion of operations.
• Clean as you go — especially before handing over any section of the Works.
• During the DNP, only essential materials can be left — and only in Engineer-approved spots.

🚨 What can go wrong?

• If the Contractor leaves debris or hazardous materials on-site, it could lead to health, safety, environmental violations, or even legal liabilities.
• Unauthorized use of surrounding land? That’s potential trespass — and might trigger claims or local authority action.
• If the Engineer wasn’t informed or didn’t agree to material retention, even a small oversight can escalate into a contractual dispute.

💡 Pro Tip:

Always get written confirmation from the Engineer on storage of materials after Taking-Over. It’s not just about formality — it protects you from assumptions and miscommunications later on.

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4️⃣ Cross-Referencing with Other Clauses

This clause doesn’t work in isolation — it’s closely tied to other parts of the contract.

🔗 Clause 4.17 – Contractor’s Equipment

• Defines what equipment the Contractor can use, such as construction machinery, tools, and vehicles that are specifically intended for use in executing the Works as outlined in the contract.
• Connects with Clause 4.23/4.22 because that equipment must also stay within site limits, meaning the Contractor is not only responsible for selecting and maintaining appropriate equipment but also for ensuring it is confined to the authorized boundaries. This ensures both operational control and legal compliance, especially when it comes to neighboring properties or environmentally sensitive areas. Proper planning of equipment placement and access routes is crucial to meeting the intent of these clauses and avoiding unintended breaches.

🔗 Clause 4.18 – Protection of the Environment

• Reinforces the obligation to minimize environmental damage by holding the Contractor accountable for sustainable site practices and proper disposal of waste materials, which directly contributes to the broader objectives of health, safety, and environmental compliance on modern construction sites.
• Gives context to why “hazardous waste” is a big deal in the 2017 update by aligning the contract with increasing global awareness and regulation surrounding toxic substances. It underscores the Contractor’s duty not just to remove visible debris, but also to identify, handle, and safely dispose of potentially dangerous materials, which could otherwise pose long-term risks to site users, the surrounding community, and even groundwater or ecosystems.

🔗 Clause 11.11 – Clearance of Site

• This is the final curtain — the ultimate and comprehensive site cleanup at the end of the contract, marking the full and final closure of all physical obligations on-site by the Contractor. It signifies that the Works are not just functionally complete but also physically cleared to the Employer’s satisfaction, ready for any subsequent use or occupation.
• While Clause 4.23/4.22 addresses the clean-up and organization required during or immediately after partial handovers (like sectional completions), Clause 11.11 ensures total clearance of all remaining Contractor’s Equipment, unused materials, Temporary Works, and any remnants of construction activities across the entire Site. This clause solidifies the Contractor’s duty to leave the Site in a neat, safe, and unobstructed condition — essentially restoring it to a state free from any operational presence. It’s the final opportunity to demonstrate professional execution and hand over a project space that is fully compliant with both contractual and legal expectations.

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5️⃣ What-If Scenarios

Let’s test the clause with some “real-world” hypotheticals.

💭 What if the Contractor stores surplus material just outside the boundary, thinking it’s fine for a day?

🚩 Even one day can be a breach. The Employer may raise a claim, especially if local laws prohibit such actions. And if someone gets hurt? Liability could escalate fast.

💭 The Contractor removes visible debris but forgets about an underground fuel tank. Is that a breach?

✅ Under 2017’s “hazardous waste” requirement — absolutely. It’s a safety and environmental hazard. Under 1999, it would be arguable, but still likely a breach of good construction practice.

💭 During the DNP, the Contractor keeps tools on site. No accidents happen, but they never told the Engineer.

📌 In 2017, that’s a technical breach. The tools should have been kept in an Engineer-agreed area. In 1999, there’s more leeway, but it’s still best to document it.

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6️⃣ Suggestions for Clarity and Improvement

Even with the updates in 2017, there’s always room for sharper drafting. Here are some ideas:

📝 Define the “Site” and “agreed areas” clearly in the Contract Data.

A vague boundary line causes real headaches — better to be precise upfront.

📦 Add categories or examples of what qualifies as “hazardous waste.”

For example: chemical containers, asbestos insulation, fuel residues — all common on design-build jobs.

🔄 Clarify the approval timeline for keeping Goods during DNP.

Should the Engineer respond in 7 days? 14 days? Add that to Particular Conditions to prevent ambiguity.

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7️⃣ Final Takeaways

Here’s what you really need to remember:

✅ Clause 4.23 (1999) and Clause 4.22 (2017) both regulate how the Contractor uses the Site — keeping things clean, safe, and confined.
✅ The 2017 update sharpens the language and adds environmental and administrative safeguards.
✅ FIDIC’s evolution here shows a broader industry trend: greater accountability, clearer boundaries, and a bigger focus on safety and sustainability.

Whether you’re a Contractor, Employer, or Engineer, this clause is your blueprint for a disciplined, organized, and dispute-free jobsite.

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Sample Letters

Notice of Differing Site Conditions

[Your Company Letterhead]
[Your Name]
[Your Position]
[Date]

[Engineer’s or Employer’s Name]
[Their Address]

Subject: Notice of Differing Site Conditions

Dear [Engineer’s or Employer’s Name],

During our recent excavation activities on [specific site location], we encountered differing site conditions that were not indicated in the contract documents. Specifically, [describe the differing condition, e.g., unexpected rock formations, underground water presence, etc.].

Given the unforeseen nature of this condition, we are seeking guidance on how to proceed. The current situation may impact our work schedule, methodology, and potentially the project’s budget.

Please advise on the necessary steps, and if required, let’s schedule a site visit to assess the situation firsthand.

We appreciate your prompt attention to this matter.

Sincerely,

[Your Name]
[Your Position]

Non-Compliance Notice to Another Contractor or Subcontractor

[Your Company Letterhead]
[Your Name]
[Your Position]
[Date]

[Other Contractor’s/Subcontractor’s Name]
[Their Address]

Subject: Non-Compliance Notice

Dear [Other Contractor’s/Subcontractor’s Name],

During our recent inspections and tests, it has come to our attention that certain aspects of your work do not conform to the specification requirements as outlined in our agreement. Specifically, [describe the non-compliance issue, e.g., the material used does not meet the required standards, the installation method deviates from the agreed-upon process, etc.].

We urge you to address this non-compliance immediately. Please review the attached inspection report for detailed information and take the necessary corrective actions.

Failure to address these issues promptly may result in further actions as stipulated in our contract. We expect all work to meet the agreed-upon standards to ensure the project’s success.

Kindly acknowledge this notice and inform us of your corrective action plan.

Thank you for your immediate attention to this matter.

Sincerely,

[Your Name]
[Your Position]

[Your Name]
[Your Position]
[Your Company Name]
[Your Address]
[Date]

[Contractor’s Name]
[Contractor’s Position]
[Contractor’s Company Name]
[Contractor’s Address]

Subject: Concerns Related to Clause 4.23 Contractor’s Operations on Site

Dear [Contractor’s Name],

I am writing to address specific concerns and deviations we have observed related to Clause 4.23 “Contractor’s Operations on Site” as stipulated in our construction contract.

1. Specific Concerns and Deviations: We have noticed [specific deviations, e.g., operations extending beyond the designated site, unauthorized personnel on site, etc.]. Attached are supporting documents and evidence that highlight these deviations.
2. Safety and Logistical Challenges: Our site supervisors have reported potential safety hazards and logistical challenges due to the aforementioned deviations. Enclosed are pictures and diagrams that illustrate these concerns.
3. Quality and Compliance Issues: Our quality control inspections have identified potential quality and compliance issues arising from the current operations. We expect adherence to the standards and requirements as outlined in our contract.
4. Potential Risks: We believe that these deviations pose financial, legal, and reputational risks to the project. We recommend considering mitigation strategies such as [specific strategies, e.g., additional insurance requirements, performance bonds, etc.] to protect the project’s interests.

We request clarification on any ambiguous language in Clause 4.23 and suggest potential amendments or additional provisions to ensure alignment with the intended scope and requirements. We emphasize the importance of adhering to the contract terms for the successful completion of the project and minimizing potential disruptions.

We propose a meeting on [proposed date and time] to discuss these concerns in detail and collaboratively find solutions or alternative approaches to address them.

Thank you for your immediate attention to this matter. We value our partnership and are confident that we can resolve these issues promptly and efficiently.

Sincerely,

[Your Name]
[Your Position]

Checklists

Checklist 1: Pre-Operation Preparation

No.	Activity	Details	Checked
1.	Boundary Confirmation	Double-check and confirm the marked boundaries of the designated Site.	[ ]
2.	Additional Area Approval	If operations might extend beyond the Site, secure written consent for the use of extra areas.	[ ]
3.	Safety Measures Setup	Establish and review safety measures, especially if the Site is near populated zones.	[ ]
4.	Environmental Precautions	Adhere to environmental guidelines to prevent potential harm to the surrounding environment.	[ ]
5.	Equipment Positioning	Position all machinery and materials strictly within the Site or agreed-upon zones.	[ ]
6.	Access Control	Implement measures to restrict unauthorized entry to the Site.	[ ]
7.	Supervisor Coordination	Maintain open channels of communication with the site supervisor for real-time updates.	[ ]
8.	Review of Contractual Clauses	Examine related clauses to ensure on-site operations align with all contract terms.	[ ]
9.	Permit Availability	Ensure all required permits and documentation are at hand and valid.	[ ]
10.	Emergency Response Plan	Set up protocols to address any potential emergencies related to on-site operations.	[ ]

Checklist 2: Ongoing Operations Checklist

No.	Task	Description	Checked
1.	Daily Site Inspection	Conduct daily inspections to ensure operations remain within designated boundaries.	[ ]
2.	Waste Management	Ensure the Site remains free from unnecessary obstructions and waste.	[ ]
3.	Report & Address Deviations	Immediately report any deviations from Clause 4.23 and take corrective actions.	[ ]
4.	Safety Audits	Regularly audit the Site for safety compliance.	[ ]
5.	Environmental Monitoring	Monitor any environmental impacts and ensure mitigation measures are in place.	[ ]
6.	Communication with Stakeholders	Maintain open communication with all stakeholders, including the Employer and Engineer.	[ ]
7.	Review of Additional Areas	If operations extend to additional areas, review the terms of the agreement regularly.	[ ]
8.	Security Checks	Conduct regular security checks to prevent unauthorized access.	[ ]
9.	Quality Checks	Ensure the quality of work meets the contract’s stipulations.	[ ]
10.	Feedback Loop	Establish a feedback loop with the team to address concerns and improve operations.	[ ]

Checklist 3: Post-Operation Checklist

No.	Task	Description	Checked
1.	Site Clearance	Ensure all equipment, materials, and waste are removed from the Site.	[ ]
2.	Environmental Restoration	If required, restore the Site to its original environmental state.	[ ]
3.	Documentation	Document all operations, especially any deviations and the actions taken.	[ ]
4.	Feedback & Review	Conduct a post-operation review to gather feedback and lessons learned.	[ ]
5.	Final Inspection	Conduct a final inspection with the Employer or Engineer to ensure all obligations are met.	[ ]
6.	Release of Additional Areas	If operations extended to additional areas, ensure they are released and restored as per the agreement.	[ ]
7.	Security Decommission	Decommission any security measures specific to the operations.	[ ]
8.	Stakeholder Communication	Notify all stakeholders of the completion of operations.	[ ]
9.	Archiving	Archive all documentation related to the operations for future reference.	[ ]
10.	Contract Closure	Ensure all contractual obligations are fulfilled before formally closing the contract.	[ ]

Checklists for Proficient Execution of Clause 4.23

Task	Responsible Party	Deadline
Review Clause 4.23	Legal Team	[Date]
Draft Initial Communication	Project Manager	[Date]
Send for Approval	Engineer	[Date]
Finalize and Send	Legal Team	[Date]

Checklists for Applying and Overseeing Clause 4.23

Task	Responsible Party	Deadline
Monitor for Compliance	Site Supervisor	Ongoing
Report Any Issues	Site Supervisor	As needed
Review Compliance Reports	Project Manager	Weekly

Checklists to Guide and Monitor the Execution of Clause 4.23

Task	Responsible Party	Deadline
Conduct Safety Audits	Safety Officer	Monthly
Review Environmental Compliance	Environmental Officer	Quarterly
Coordinate with Other Contractors	Project Manager	As needed

Flowcharts

Detailed Explanation of the Flowchart

1. Start: Contractor Commences Operations on Site
   • This marks the beginning of the contractor’s physical activities on the project site. It’s a critical phase where the contractor mobilizes resources and sets up for the construction work.
2. Confine Operations to Site and Agreed Working Areas
   • The contractor must strictly limit their operations to the designated construction site and any additional areas that have been agreed upon with the Engineer. This confinement is crucial to prevent unauthorized use of land and to minimize disturbances to surrounding areas.
3. Ensure Equipment and Personnel Stay Within Designated Areas
   • It’s imperative that all construction equipment and personnel remain within the boundaries of the construction site and agreed working areas. This step is essential for maintaining safety, order, and compliance with legal and contractual boundaries.
4. Keep Site Free from Unnecessary Obstruction
   • The contractor is responsible for keeping the site free from any obstructions that are not essential to the construction work. This involves efficient site management to ensure that the work progresses smoothly without any unnecessary hindrances.
5. Store or Dispose of Surplus Materials and Equipment
   • Proper management of surplus materials and equipment is a key responsibility. The contractor must decide whether to store these materials for future use or dispose of them responsibly. This decision impacts site cleanliness, safety, and cost-efficiency.
6. Remove Wreckage, Rubbish, and Unneeded Temporary Works
   • Regular site clean-up is mandated to remove any wreckage, rubbish, and temporary structures that are no longer needed. This step is crucial for maintaining a safe and efficient working environment.
7. Upon Taking-Over Certificate: Clear Specified Site Area
   • When a part of the project reaches completion, as evidenced by the issuance of a Taking-Over Certificate, the contractor must clear that specific area of the site. This includes removing all construction-related materials, equipment, and debris.
8. Leave Site Area in Clean and Safe Condition
   • The cleared area must be left in a condition that is safe and clean. This requirement is not only a matter of contractual compliance but also a reflection of the contractor’s professionalism and commitment to safety and environmental standards.
9. Retain Necessary Goods for Defects Notification Period
   • During the Defects Notification Period, the contractor is allowed to retain on-site any materials or equipment necessary to address potential defects or complete outstanding work as per the contract.
10. End: Contractor Fulfills Obligations Under Contract
    • The process concludes when the contractor has successfully fulfilled all their contractual obligations related to site operations. This includes managing the site throughout the construction phase and ensuring its proper clearance and condition at the end of the project.