Technical map view of the Cologne administrative district with Cologne marked for explosive ordnance investigation and surveys by FONTANA-EOD

Explosive ordnance surveys in Aachen

Before an explosive ordnance investigation in Aachen, more than the construction plans must be available. Access to the site, known utilities and planned specialist foundation works also need to be clarified. FONTANA-EOD helps you coordinate the investigation requirements using your plans and the available authority documents.

Records

Compare the assessment with the construction plans.

Work area

Clarify access and existing utilities.

Execution

Consider specialist foundation works separately.

Discuss an investigation for your projectExplosive ordnance assessment in North Rhine-Westphalia
Assess the construction project

Prepare the application to the authority and the working information together

For your construction project in Aachen, the status of the municipal application and the practical requirements for the investigation are clarified together. These include the affected areas, planned intervention depths, access and existing utilities. FONTANA-EOD supports the technical preparation and carries out the agreed permissible investigation scope. The City of Aachen manages the local administrative procedure; the state explosive ordnance disposal service is involved in accordance with its responsibilities.

Project references

Selected project examples

Project site

Connect the site with the specific construction task

Schematic map with the North Rhine-Westphalia coat of arms, beside a tablet, safety helmet and notebook.

Assign the Aachen site to the specific application

Aachen is a member city of the StädteRegion Aachen with the legal status of an independent city and belongs to the Cologne administrative district in North Rhine-Westphalia. For an enquiry within the city, state the exact project address, for example in the city centre or inner ring, Burtscheid, Hörn or Westviertel, Brand, Eilendorf, Laurensberg, Richterich or Forst. Projects in Würselen, Eschweiler, Stolberg (Rhld.), Herzogenrath, Alsdorf, Baesweiler and other surrounding municipalities or districts are assigned to the respective municipality separately. Place details support the allocation of responsibilities and project planning. What matters is the specific area of intervention, the information available for it and the procedure applicable at the project location.

North Rhine-Westphalia
Local context

Historical information and the current application procedure

Municipal application procedure

The City of Aachen describes aerial photograph analysis as the first step in preventive explosive ordnance disposal. For an application, it identifies a planned construction project involving ground disturbance and refers to the procedure after a building permit has been granted. Use the current forms and procedural guidance on the municipal service page for your application.

The City of Aachen documents several weeks of fighting in and around the city and the surrender of the encircled Wehrmacht on 21 October 1944. The North Rhine-Westphalia Ministry of the Interior identifies the ground war around Aachen as a historical background to present-day ordnance finds. This information is linked spatially through the assessment of Aachen's urban history to the available property documents. The current investigation task is determined from the specific information about the project area and the planned ground disturbance.

Working information for the investigation

At the same time, clarify whether the site may be entered, which utilities are known and at what construction stage the investigation will take place. The appointed specialist company needs this information to prepare its work. The required application to the authority remains unaffected.

Urban infill in the city centre, work on older railway or transport facilities and the conversion of industrial or commercial land require different documents. Documented war damage, former uses, demolition, infilling and subsequent ground movements are considered where known. The same project-specific comparison applies to former combat areas near the border. For an alteration, describe which underground structures will remain and where additional working space or deeper connections are planned. Historical indications, the current construction condition and the planned intervention each receive a traceable spatial reference.

Working together

Allocate tasks within the construction project

Client and operator

The client describes the project and provides the available project documents. The operator adds requirements relating to use, access and scheduling. Before an appointment, it is recorded clearly which information is missing, who will obtain it and which decision the result is intended to support.

Planning and construction management

The specialist designers describe areas, depths, construction methods and changes. Site management coordinates the planned sequence with the construction contractors and agreed specialist works. Results are assigned to the respective intervention. A technical plan change is communicated early enough for its effect on the survey task to be assessed before construction. Organisational construction stage boundaries remain distinguishable from technical survey boundaries.

Specialist company and competent bodies

The private explosive ordnance specialist company carries out the agreed permissible investigation and documentation scope. Authority requirements and decisions are clarified with the respective competent bodies. The documents needed for a specific procedure depend on the site and project. The technical report documents the specialist service performed, including areas, depths and limits of its conclusions. Its applicability to further groundworks is checked against the specific intervention.

The City of Aachen manages the local procedure within the city. The state explosive ordnance disposal service of the Düsseldorf District Government supports the local public order authorities in the Düsseldorf and Cologne administrative districts. For a project in the surrounding area, the competent municipality is determined from the actual project address. Any required official appointment and the special conditions for private activities under North Rhine-Westphalia's Explosive Ordnance Ordinance are clarified before work.

Investigation task

Which specialist task comes next?

Check the status of the municipal procedure

For Aachen, the current forms and guidance are checked against the available documents. State which assessment is already available and which measures follow from it. A private enquiry is additionally related to the specialist support required. Necessary applications to the authorities remain part of the prescribed municipal procedure.

Assess historical documents

Define the legal and technical boundaries of the task

For activities in North Rhine-Westphalia, the requirements of explosives legislation and the Explosive Ordnance Ordinance are checked together. What matters is the work actually planned, any required official appointment or applicable statutory exceptions, and all conditions associated with them. The agreed private contract is defined on this basis. The authority's assessment of the ordnance situation and responsibility for hazard prevention are recorded in the project file.

Compare investigation methods
Project types

Prepare the investigation with complete working information

Illustration: two people with a tablet beside a drawing table and a survey trolley on a construction site.

Bring the application area and the actual intervention together

The technical contract requires the excavations, utilities and other interventions actually planned. Add their locations and depths to the plan. The property boundary alone describes neither the construction task nor the investigation scope. Existing assessments are compared with this specific stage of planning. Unclear or not yet defined areas remain expressly identified.

Mark the structure, excavation and additional working spaces separately from the outer property boundary. A site plan from an earlier design phase may show different foundations or access arrangements. Record which plan version underlies the enquiry and which option is now binding. The technical review assigns existing results to the areas actually affected. For areas or depths added later, the additional information requirements are coordinated before the intervention.

Specialist services and investigation tasks
Illustration: two people review plans and documents at a table beside a construction vehicle.

Utility documents are incomplete

Mark known utilities and unclear routes. The statement and supplementary as-built plans must reflect the actual state of knowledge. Utility information is working information; it does not demonstrate an explosive ordnance investigation. The responsible participants clarify missing information before deriving a suitable execution method. The status of the application to the authority remains separately traceable.

For a connection outside the previous work site, the route, crossings and planned chamber locations are related to the current utilities. Unclear information remains expressly identified as such. Changes by utility providers are incorporated with a date and plan reference. The responsible participants determine which information is missing for the investigation and how it will be obtained. Preparatory trial trenches or breaking-out works are also treated as ground interventions in their own right, with the protection and investigation prerequisites they need.

Document findings and their limitations
Illustration: a person with survey equipment in a marked construction area; an excavator with a drilling attachment stands on the right.

Pile foundations or retaining works are added

New deep interventions may extend beyond the task previously described. Provide positions, construction methods and depth references. The existing information is checked against this scope. The permissible appointment procedure in North Rhine-Westphalia is also clarified for the specific activity. An investigation of other parts of the site or shallower depths is not transferred without evidence.

When the foundation design changes, the new pile positions, retaining-wall alignments and relevant depths are compared with the points considered previously. Add sections, the elevation reference and planned geometric deviations. The specialist designers assess which conclusion is needed for the new volume of intervention and which permissible method is suitable. Results from neighbouring points are checked against their documented scope. The subsequent task description identifies the areas actually to be investigated and the information still outstanding.

Understand downhole surveys
Preparation

Prepare the scope and commission together

The following specialist topics explain possible investigation tasks. Which activity may be privately commissioned under the specific North Rhine-Westphalia procedure is clarified separately before an agreement.

Establish what needs to be known before commissioning the work

First establish which decision the commission needs to support. Is the task an initial assessment of existing documents, an investigation of a specific area or examination of an anomaly that has already been assessed? These tasks require different evidence. A general wish for safety does not define an investigation that can be carried out. The enquiry therefore specifies the groundworks, location, depth and available findings. Suitable specialist work and the required reporting are then agreed on that basis.

Define the specialist task

Coordinate preparatory work with the investigation

Required access and survey conditions are clarified before the site visit. This may include keeping areas clear, obtaining service information and coordinating with other trades. The method and site determine which preparations are actually needed. Changes to the surface or additional groundworks are not undertaken unilaterally simply to prepare for a survey. Their sequence is agreed with the specialist designers and responsible parties.

Clarify preparatory work in the programme

Agree a clear scope and schedule

The scope of private specialist work is agreed using the project documents, actual execution conditions and permissible activity. Necessary preparatory works, investigation, evaluation and documentation are described transparently. Costs and dates are related to these prerequisites and the required coordination. Changes to the construction plans are checked against the agreed contract before work is extended.

Discuss the scope and schedule
Tasks at the site

What is needed for the investigation

01

Site plan of the investigation area

The area should be shown so that it can be assigned unambiguously to the planned ground disturbances. Mark excavations, utility trenches and other relevant works. A property outline alone explains neither the intended depth nor the location of individual structures.

02

Access and permission to enter

Clarify access and the necessary consents for the areas concerned. For its explosive ordnance investigation application, the City of Aachen requires, among other things, permission to enter. Also agree with owners or users when work may take place and under which conditions. A declaration accepting the costs and a site plan are also prepared for the municipal investigation application in accordance with current procedural requirements. Other properties affected and the permission to access them are considered during preparation. If the applicant and property owner differ, the owner's necessary consent is obtained. Agreed access also considers neighbouring areas where equipment will be placed or access routes used. Before execution, the respective participants receive a clear description of the areas concerned.

03

Utilities and existing installations

Aachen identifies the declaration concerning the absence of utilities and as-built plans for existing utilities as required documents. Information should reflect the condition actually known. Mark unclear utility routes and known metallic installations so that limitations can be considered during preparation.

04

Specialist foundation engineering activities

Identify driving works, pile foundations or retaining works separately where planned. The city refers to the explosive ordnance disposal service's guidance for these activities. Add the proposed methods and the location and depth of each intervention to the earthworks plan.

Project documents

Documents that establish the next step

Keep the complete attachments with the application

A report or information from an authority is kept with its associated maps. It must be possible to relate the current plan version to them. Missing attachments are requested. This allows subsequent coordination to identify which area was intended and which additional conclusion is still required.

Assign the city's response, the aerial photograph assessment and associated attachments to the same file reference and property area. Where there are several applications, it remains clear which construction section a decision or requirement concerns. Newly submitted plans receive a version reference so that subsequent work uses the current intervention geometry.

Keep access and investigation separate

Permission to enter enables the agreed use of an area under its respective conditions. It is not a technical conclusion about explosive ordnance. Clarify both access and the necessary investigation. Restrictions imposed by owners, users or installations are communicated promptly and considered in planning. The measurement data, survey results and assessment belonging to the investigation contract are assigned to the area worked through the complete report and its plan attachments. After clearance works, the clearance record, including its scope, results and remaining limits, supplements this evidence chain for the construction management team.

Construction sequence

Coordinate investigation and construction sections

Before fixing a date

Bring together the status of the authority documents and the working information required. Check the site plan, access and utility information in particular. Outstanding points are identified before execution. A requested date alone does not demonstrate that the necessary conditions are already in place on site.

Coordinate the construction phase with us

Before changed groundworks begin

Compare the current construction works with the area investigated and its depths. Additional foundations or relocated utilities are communicated in advance. The specialist designers clarify which conclusions still apply and which steps need to be added. Where authority requirements are affected, the procedural status is checked as well.

Coordinate the construction phase with us
Method selection

Select methods according to the task and survey conditions

Historical records and aerial photographs

Historical aerial photograph assessment and other old records help place the basis for suspicion in its spatial context. The available images, their evidential value and the limits of the area considered matter. The absence of an identifiable indication must be distinguished from a technically surveyed ground area. The assessment is considered together with the planned intervention and other available findings. It can support the choice of a survey, but is not a measurement of the present-day subsurface or confirmation for all future works.

Understand aerial photograph assessment

Magnetometric survey

Magnetometric methods detect magnetic anomalies. Whether they can address the specific investigation task depends, among other things, on the expected objects, subsurface conditions, interference and investigation area required. Fences, utilities or existing structures can affect interpretation. A signal is therefore not classified as explosive ordnance solely on its strength. The method, interpretation and any further investigation are planned as a connected specialist task. Magnetometry measures the magnetic field passively. The magnetic effect of the target object is decisive; electrical conductivity alone does not establish its detectability by this method.

Understand the scope of magnetometry

Electromagnetic methods

Electromagnetic investigations may be suitable for certain metallic target objects and site conditions. Suitability is justified for the particular task rather than inferred from the mere availability of an instrument. Interfering installations, accessible areas and the required conclusion must also be considered. Results are documented with their locations and investigation conditions. Whether a supplementary method is needed follows from technical assessment and remains a specific project decision. Transient electromagnetic methods, or TDEM, evaluate the time-dependent electromagnetic response of conductive objects. The method is selected according to the investigation objective and actual measurement conditions.

Understand electromagnetic surveying

Ground-penetrating radar

Under suitable conditions, ground-penetrating radar can provide information about subsurface structures and reflections. Ground conditions, moisture, installations and the particular survey task affect interpretability. An anomaly is not automatically ordnance, and an area with no apparent anomalies is not general evidence for arbitrary depths. The specialist interpretation and its limits are documented with the instruction. A survey for another purpose is not adopted without checking as ordnance evidence.

GPR and limitations

Deep-ground and downhole surveys

For deeper groundworks, it may be necessary to establish whether a surface investigation can provide the required findings or another approach is needed. Preparation includes the location, depth, borehole layout and existing services. Creating access for the investigation must also be properly planned by specialists. A general depth figure or standard grid cannot replace that work. Findings remain limited to the areas actually investigated and the method used.

Prepare deep interventions

Survey during construction

If a necessary preliminary investigation cannot be completed, the specialists assess whether a planned approach during construction is suitable. This includes coordinated investigation, interpretation and communication of findings within the intended work sequence. Visual observation of excavated material is not an interchangeable substitute for a necessary survey. Site management needs a clear description of when specialist work will take place, how new findings will be handled and which areas remain unresolved.

Agree the approach during construction
Technical assessment

Coordinate investigation scope and methods

Compare the assessment with the construction project

The historical aerial photograph analysis is related to the project. Indications or specific suspected points must be read together with the further steps intended for them. A general statement about Aachen's history is not evidence for an individual construction plot and does not replace site-specific documents.

Reusing an older report requires the text and all associated plans together. Check whether the coordinate system, former ground surface and documented depths fit the present project. After demolition or infilling, the current surface may differ from the former reference level. These changes are traced using the available as-built information. Missing attachments and unclear area boundaries are queried before the result is used. The comparison remains in the project file even if the designers or construction managers change.

Check access and measurement conditions

Whether a surface survey is technically suitable depends on the investigation objective and site conditions. Existing installations or restricted access can affect coverage. Where limitations are identified, they must be stated and necessary supplementary measures coordinated.

For several construction sections, the investigation areas actually accessible are coordinated with the planned construction sequence. Identify access routes still in use, occupied areas and temporarily restricted access. The investigation documents the conditions under which the data were collected. Areas exposed later and changed interference conditions are considered separately when work continues. The report and plan attachments show which sections have been worked and which part of the planned task remains outstanding. The next construction phase is prepared using this information.

Agree on areas, depths and methods

The survey is planned for a defined area and depth range. Any supplementary methods required follow from the available information, the construction task and applicable requirements.

Next steps

From enquiry to documented investigation

01

Clarify procedural status

Check which authority documents are available and which applications are still needed. For initial contact, state the project address, parcels, construction task and a contact person. Existing information, reports and complete attachments are checked for currency, spatial and depth references, and outstanding information. The municipal procedural steps still required are assigned to the project.

02

Complete the working information

Bring together the site plan, access, utility information and construction methods. If historical information is needed for an appointed specialist supplementary task, we carry out the necessary source research and aerial photograph analysis and assign the results to the present area of intervention. The official aerial photograph assessment is initiated through the prescribed municipal application procedure.

03

Agree on the task

Record the investigation objective, limits and prerequisites. Method selection considers expected objects, ground conditions, interference and accessible areas. The permissible activity scope and required authority involvement are clarified before execution.

04

Perform the agreed investigation

The survey or investigation during construction appointed under North Rhine-Westphalia's requirements is carried out in the agreed areas and points. Measurement data and observations receive traceable location and elevation references. Uninvestigated areas, restricted access and relevant interference are recorded.

05

Assess survey data and findings

The collected data and findings are evaluated against the investigation objective. The technical assessment considers interference, the areas reached and remaining limits of the conclusions. It establishes which further investigation or work is needed for the planned groundworks.

06

Bring the report and plan appendices together

The report and plan attachments document the specialist works performed and their assessment. Worked areas, investigation depths, the relevant ground surface and limitations remain assigned. Reused older results and newly investigated areas are recorded distinctly. The agreed recipients receive the related documents together.

07

Put the result in context

Check which planned works the investigation result covers. Using the results and their limits, the participants coordinate the further specialist tasks. The competent bodies make the necessary authority decisions. A new depth, additional area or changed construction method is compared with the documented scope before further groundworks.

Documentation

Document investigated areas and areas not covered

Findings and their scope

A traceable report connects the result to the area investigated, depth reference and relevant conditions. It should show whether limitations existed and which areas were not covered. Subsequent planning also needs to establish whether later changes to excavations, utilities or construction methods are still covered by the documented scope.

Project responsibilities

In North Rhine-Westphalia, hazard prevention rests with the local public order authorities; the state explosive ordnance disposal service supports them. FONTANA-EOD documents the agreed permissible specialist work and provides the associated results for further coordination. Authority requirements and decisions are clarified with the competent bodies. The technical report remains linked to its investigation objective, the areas and depths worked, and the limits of its conclusions.

Working approach

How FONTANA-EOD works

Document the agreed specialist service clearly

We assess the planned groundworks against the available documents and their design revision. Before attending site, we agree with you what needs to be investigated, which areas are accessible and what findings are required. If the design or site conditions change, we check whether the agreed scope remains appropriate. The report states what was actually investigated and the limits of the findings. This allows designers and site management to see which findings they can use and where questions remain.

Discuss the investigation task

The task before the equipment

We first establish the investigation objective: which question must it answer? We then select a technically suitable method. The availability of a particular device or experience on a similar neighbouring site is not enough to justify the choice of method on its own.

Keep limitations visible

Inaccessible areas and limited conclusions are identified. They do not disappear into a total area figure. Designers and site management can then decide specifically which areas still need attention and when a suitable survey becomes possible.

Clarify changes before intervening in the ground

A new location, additional depth or different construction method is compared with previous results. A familiar project name does not replace this comparison. Feedback is provided before the affected work so that an outstanding question can be included in the sequence.

Hand over the report and plan together

The technical conclusion remains connected to its location references and appendices. A brief summary helps orientation but does not replace the documented survey scope. This basis is retained even if site management or contractors change.

Understand the results

Use technical statements for the next decision

Bring working information and investigation results together

Permission to enter and utility information describe prerequisites for execution. The investigation report documents the specialist work actually performed and its spatial and technical scope. Both types of document are assigned to the project. For further groundworks, the planned intervention is checked against the documented investigation results.

Understand investigation reports and their limitations

Retain plan versions and depth references

Changed execution is compared with the existing results using its location and depth. The plan versions used must therefore be unambiguous. A new drawing does not extend an old report. Document the change and the resulting technical assessment before the affected works.

Understand the service scope
Design and findings

Documents for the next construction decision

Illustration: aerial photographs and maps on two screens and printed on a desk.

Historical evidence and the current design

Aerial photograph interpretation is related to the actual groundworks. Its purpose and geographical scope remain distinct from a technical investigation of the ground as it is today.

Understand aerial photograph assessment
Illustration: two people review plans and documents at a table beside a construction vehicle.

Specialist reports for site management

The findings, their locations and limitations are handed over together. This makes clear to those carrying out the work which area has been investigated and which task remains outstanding.

Assess investigation reports
Four people in orange high-visibility vests in front of two excavators on a construction site.
Person with a yellow survey cart on a footpath in front of a hedge.
Questions from planning

Questions about preparing an explosive ordnance investigation in Aachen

Where can I find the current Aachen application forms?

The municipal explosive ordnance disposal service page links to the application forms and supplementary sheets. For the specific project, the conditions stated there and the current procedural status should be checked. An enquiry to FONTANA-EOD does not replace the required application to the authority.

Does a declaration concerning the absence of utilities already constitute an explosive ordnance investigation?

No. It concerns working information for the investigation. Where utilities are present, the city requires corresponding as-built plans. Utility routes and their assessment must be distinguished from an investigation for explosive ordnance.

What additional information is needed for pile foundations or retaining works?

Identify the activities actually planned, including their locations and depth references. Aachen refers to separate explosive ordnance disposal service guidance for such specialist foundation works. The investigation that follows must be coordinated using the project and available information.

Can a small ground intervention automatically be assumed to be safe?

No. A general depth figure or small area does not support a conclusion about the specific property. What matters is the available information, the planned intervention and the requirements applicable to the project. Outstanding questions must be clarified before execution.

What should I do if I find possible ordnance?

Stop work in the affected area immediately and keep your distance. Do not touch, move or take the object. Notify the police on 110 and follow the instructions of the competent authorities. The normal project contact route is not suitable for urgent reports of finds.

Is the property boundary on the site plan sufficient for technical preparation?

The specific groundworks are also needed, including their locations, areas and depths. Excavations, utilities and individual foundations should be identifiable. The property outline alone does not adequately describe the investigation contract.

What should be communicated about unclear utility routes?

Indicate the actual state of knowledge and attach available as-built plans. Missing information is clarified with the responsible participants. A declaration should not assume an unverified absence of utilities.

Which factors determine the costs and handling of an enquiry?

The status of the authority procedure, complete documents, access and the specific investigation determine preparation. Planned specialist foundation works and known limitations are identified separately. The private service scope must fit the permissible procedure in North Rhine-Westphalia. Calculating private specialist works particularly considers area and depth, permissible investigation method, access, interference, necessary preparatory works and documentation scope. Official services and the company's own contractual services are allocated separately under their respective cost rules or agreements.

Project enquiry

Discuss your Aachen investigation site

Send the application status and intervention details

Provide current authority information, the site plan, intervention depths and existing reports. Mark additional piles, retaining works and other changes. Using this information, we discuss the necessary investigation and any preparatory works or documents still missing. Enquiries about surface surveys or area clearance are checked against the specific investigation objective and the service scope permissible in North Rhine-Westphalia.

Complete the working information

Identify access routes, permission to enter, available utility plans and unclear information. Describe the site's condition at the proposed investigation date and the responsible contacts. Also state which groundworks are to start first and which areas are not yet accessible. Necessary preparatory works and handover of results can then be coordinated in time. Add missing parts of the application, existing file references and the intended construction section.

GPR on a construction site
Project enquiry

Have your project assessed

Whether historical aerial photograph analysis, explosive ordnance surveying, surface surveying using GPR, magnetometry or TDEM, deep-ground surveys, downhole surveys, excavation supervision, area clearance or ordnance recovery is needed depends on the location, ground disturbance, depth, ground and existing documents. An early ordnance assessment provides clarity for tendering, programming, occupational safety and construction.

FONTANA-EOD combines its Section 7 SprengG licence, specialists holding Section 20 SprengG certificates of competence, suitable survey and clearance methods, and traceable documentation. Send the site plan, depth of ground disturbance, construction phase and existing documents for an initial technical assessment.

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