Technical map of the administrative district of Arnsberg, marking Arnsberg as a location for ordnance investigation and surveying by FONTANA-EOD

Explosive ordnance surveying for changes of use in Dortmund

A change of use may involve demolition, utility lines and access alongside new buildings. Explosive ordnance assessment must consider the groundworks planned for these tasks. For your project in Dortmund, FONTANA-EOD helps compare existing results with the proposed construction sections.

Change of use

Consider demolition and new construction together.

Site development

Also record connections and crossings.

Handovers

Relate results to the correct subareas.

Assess the construction project

Consider all groundworks for a change of use together

When a property is redeveloped, demolition, new buildings and site servicing may affect different areas. For your project in Dortmund, we compare these interventions with existing results and the official procedural status. Handovers between construction sections are prepared with their limitations of findings. Incorporate the local procedure and investigation before the first ground intervention in each case into planning.

Project references

Selected project examples

Project site

Connect the site with the specific construction task

Schematic map with a coat of arms, alongside a tablet, safety helmet and notebook.

Assign the Dortmund project to the appropriate procedure

Dortmund is an independent city in North Rhine-Westphalia and belongs to the Arnsberg administrative district. The city’s Ordnungsamt is the local contact, supported technically by the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg district government. Property location, planned ground interventions and existing knowledge are brought together for coordination. The appropriate procedure is clarified for the actual construction project.

An enquiry from Innenstadt-West, Innenstadt-Ost, Innenstadt-Nord, Huckarde, Dorstfeld, Eving, Hörde, Scharnhorst, Hombruch or Mengede needs the specific address and a site plan. For a change of use, retained buildings, new construction areas and connections are shown together. In railway, road and utility areas, affected operational areas and usable access are included. A district name establishes neither ordnance contamination of the property nor a specific investigation method.

FONTANA-EOD has a location in Wesseling. For a project in Bochum, Castrop-Rauxel, Lünen, Witten or Unna, state the respective municipality and precise project location. These places have their own municipal responsibilities. The procedure is therefore clarified for each project location, not inferred from processing of a neighbouring Dortmund project. For other projects in the Ruhr area too, location, groundworks and existing results are clearly identified.

Local context

A new use affects more than the eventual building

Shared peripheral areas between construction commissions

When a formerly commercial property is redeveloped, some buildings may be retained while others are demolished and new routes or connections installed. Consider all ground interventions planned for these tasks when preparing explosive ordnance assessment. Division into different construction commissions must not leave shared peripheral areas or connection routes out of the documents.

The LWL portal on Westphalian history documents the air raid on Dortmund on 12 March 1945 and the importance of transport links at that time. Historical information is related to today’s property using its actual location and history of use. Available records and former construction conditions are reviewed for former steel and mining sites, railway and shunting areas or former storage and military sites. Reconstruction, rubble clearance, fill and later changes may distinguish today’s ground from an older plan version. Such indications establish a specific question for further work, not a blanket claim of ordnance contamination across a district.

Responsibilities and procedure in Dortmund

In Dortmund, the Ordnungsamt is the local contact for explosive ordnance assessment, supported by the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg district government. Municipal guidance also covers projects exempt from the building control procedure and particular processes for large special-purpose buildings. Clarify the applicable procedure early using the specific project. For large special-purpose buildings, municipal guidance states that building control checks the relationship to suspected areas and involves the Ordnungsamt. For other projects, clarify the respective intended application procedure. Early coordination also concerns procedure-exempt works involving ground interventions. Official information already received is submitted with the current areas and depths.

Working together

Distinguish the tasks of client, designers and specialist contractor

Client and operator

The client describes the project and provides the existing project documents. The operator adds the requirements for use, access and timing. A named contact coordinates the assigned tasks with those responsible. Before commissioning, a clear record is made of which information is missing, who will obtain it and which decision the results are intended to inform.

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 addresses the agreed investigation and documentation scope permissible for the activity. Official requirements and decisions are clarified with the respective competent authorities. In Dortmund, the Ordnungsamt is the local contact, supported by the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg district government. Building control and other specialist departments undertake the tasks for which they are responsible in the specific project. FONTANA-EOD’s report documents the specialist service actually performed, its investigation purpose and remaining limitations.

Investigation task

Which specialist task comes next?

Review investigation requirements for the entire project

The official assessment and earlier results are compared with demolition, site servicing and new construction together. Individual intervention areas and depths remain distinguishable. A former use does not create a blanket finding about the ground. Technical preparation shows which findings apply and where further clarification is needed.

Assess historical documents

Clarify execution conditions before method selection

Retained facilities and new installations influence the investigation options available. Therefore describe the condition that will actually exist at each investigation appointment. A suitable method must match the task and conditions. A permissible private commission and necessary state measures are clarified with the responsible participants before agreement.

Compare investigation methods
Project types

Coordinate the change of use across all construction sections

Illustration: a person wearing a hard hat and holding a tablet beside a cordoned-off excavation with an excavator.

Identify the earliest ground intervention

A change of use does not always start with the new excavation. Removing old foundations or laying a connection may already require groundworks. Show these steps on the shared site plan. Each intervention needs the appropriate documents. A later investigation appointment for the new building does not answer questions concerning an earlier working section. Also mark temporary routes, additional connection excavations and works to remove underground structural elements. The client and specialist company can then identify the findings needed before the earliest demolition step.

Provide specialist supervision of excavation
Illustration: two people review plans and documents at a table beside a construction vehicle.

Plan site servicing before new installations

New utilities and structures change the conditions for later investigation. The sequence is therefore technically agreed early. Identify which areas are accessible together and which become available only later. A date agreed between contractors must be compared with the investigations needed and official steps still outstanding.

Coordinate the sequence and tasks
Illustration: two people review plans and documents at a table beside a construction vehicle.

Keep interfaces between subareas visible

Demolition, site servicing and new construction may concern adjoining areas. Relate their respective results to the areas actually addressed. Peripheral strips, additional chambers and later crossings remain separately identifiable. A completion notification for one construction section does not establish complete investigation of connections for the next section.

Document findings and their limitations
Preparation

Prepare the scope and commission together

For commissioning, the investigation objective, local procedural status and permissible private activity scope are considered together. Demolition, site servicing and new construction remain identifiable with their respective interventions.

Establish what needs to be known before commissioning the work

For the commission, first clarify which decision is to be prepared. Is the task initial interpretation of existing documents, investigation of a particular area or work on an already assessed finding? These tasks need different underlying information. A general desire for safety does not describe an executable investigation scope. The enquiry therefore identifies the intervention, position, depth and available knowledge. Suitable specialist works and results documents needed are then agreed. Complete existing reports with their maps and appendices are provided for a quotation. Identify which findings are already usable for the next planning step and where knowledge remains missing. For property acquisition or a later partial handover, describe the construction sections concerned explicitly. The commissioned specialist task thereby retains its actual area and depth references.

Define the specialist task

Coordinate preparatory work with the investigation

Access and measurement conditions required are clarified before the appointment. This may include areas to keep clear, available utility information and coordination with other trades. Preparatory works actually needed follow the chosen method and site. Surface changes or additional interventions are not undertaken on personal initiative solely to prepare a measurement. Their sequence is agreed with specialist planners and the responsible participants. Identify known utilities, retained foundations and areas actually available at the proposed time. If clearing or other preliminary works are needed, their scope and responsible participants are agreed beforehand. Access to the area and its technical investigability are assessed separately.

Clarify preparatory work in the programme

Agree a clear scope and schedule

A reliable sequence distinguishes work already technically clarified from outstanding requirements. If an area will be only partly accessible, commissioning must consider this. Results handover and assessment also need time in the construction sequence. Costs and dates are agreed for the described specialist task and actual execution conditions. Specific coordination connects the described scope with access, documents, execution conditions and the decision date needed. Costing depends, among other things, on investigation area size and subdivision, investigation points needed, accessibility, preliminary services, assessment and documentation. State measures, private specialist works and preparatory works by construction participants are assigned separately in the sequence. If scope or construction sequence changes, the affected effort is discussed with the client.

Discuss the scope and schedule
Tasks at the site

Groundworks belonging to the change of use

01

Remove foundations, basements and utilities

Distinguish above-ground demolition from work on foundations, basements or underground utilities. Show which structural elements are to be removed and where ground is affected. Investigation needs the positions and depths of these works; a demolition date alone is insufficient. For a former industrial or commercial site, available information on basements, excavations and filled structures is included. A demolition plan and known ground levels help compare today’s construction task with previously investigated areas. Unresolved areas are explicitly identified before they are addressed.

02

Consider existing installations

Mark buildings, utilities and operational areas that will remain. They may influence access and measurement conditions in the adjacent construction area. Show retained installations and new structural elements together on the site plan so that the investigation area can be clearly defined.

03

New routes, utilities and crossings

Record site servicing through to its actual connection points. A chamber or crossing outside the new buildings may raise its own investigation question. Temporary interventions also belong in the description if proposed for the construction sequence. For a temporary utility or site connection, identify the start, end and corresponding excavations clearly. Give the plan to the specialist company even if another contractor performs these preliminary works. A later change of alignment is communicated before the affected intervention.

04

Construction sections separated in time

Record which areas are available simultaneously and which become accessible only later. Match investigation to this timing. Existing results must be clearly assigned to each subarea; one section’s status does not automatically apply to the next.

Project documents

Documents that establish the next step

Keep a shared plan overview

Participants need an overview with clearly labelled construction sections and plan versions. It refers to individual reports and records known limitations. If a connection moves or an area is added later, communicate the change to the design teams concerned. The overview supports identification and does not replace complete documentation. For further use, retain the plan designation, date and spatial reference. Additional depth or a moved structural element position is compared with the previous investigation scope. Specialist planners and site management can then identify the clarification still needed for current execution.

Establish responsibility for handover

Before contractors change, establish who passes on reports, appendices and outstanding tasks. The next site management team must be able to relate findings to its own working area. A single results line is often insufficient. Outstanding local coordination also remains part of handover. For completed clearance works, the clearance record with documented clearance scope and results belongs in these handover documents. Alongside the result, pass on the areas actually addressed, relevant depths and known investigation limitations. When works resume, compare current conditions with that basis. Changed or still inaccessible areas remain identifiable as outstanding tasks for the next construction phase.

Understand the results

Use technical statements for the next decision

A partial report remains limited to its area

Investigation of one section may assist subsequent planning. Its findings are used only within the documented areas, depths and conditions. Additional construction works require another comparison. Passing a report to another contractor does not extend its scope.

Understand investigation reports and their limitations

The construction sequence influences preparation

Access and measurement conditions may change during site servicing. Technical coordination before new installations helps consider these dependencies. The sequence is established using the project. It cannot be inferred solely from the eventual completion date desired.

Understand the service scope
Construction sequence

Coordinate investigation and construction sections

Before demolition

Show underground works independently of above-ground demolition. Compare existing results with these areas. If access must first be provided, that sequence also needs technical clarification. The construction schedule should show the actual requirement rather than assigning every question to the later new-build section.

Before handover for site servicing

Check utility alignments, chambers and crossings against previously documented investigation areas. New installations may change later measurement conditions. The appropriate timing and further steps needed are therefore agreed before execution. The next construction phase receives complete reports and knows the unresolved areas remaining.

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 survey task depends, among other things, on the expected objects, ground conditions, interference and required survey area. Fences, utilities or existing structures may affect interpretation. A measurement signal is therefore not described as ordnance solely because of its strength. Method, interpretation and any further investigation are planned as a connected specialist task.

Understand the scope of magnetometry

Electromagnetic methods

Electromagnetic investigations can be suitable for particular metallic targets and site conditions. Their suitability must be explained for the task, rather than inferred simply from the availability of equipment. Interfering installations, accessible areas and the findings required must also be considered. Results are documented with their location and survey conditions. The specialist assessment determines whether a supplementary method is needed; this remains a project-specific decision.

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

When investigation should take place

Compare existing results with the plans

The historical aerial photograph analysis and existing investigation reports must be compared with the planned intervention. Former operational use or a location beside a railway does not replace this evidence. Area changes and new connection routes should be identifiable against the previous documents.

Check measurement conditions before new installations

For a surface survey, installations and other interference are technically relevant. New utilities or structural elements may change the conditions for later investigation. Before construction starts, therefore clarify when investigation must take place relative to site servicing works.

Clarify the permissible commission

The survey must be placed within the respective permissible commissioning relationship. The KampfmittelVO NRW provides narrowly defined exceptions for certain private activities. A privately agreed investigation replaces neither outstanding state steps nor necessary official coordination for the project.

Next steps

Coordinate construction sections and investigation

01

Record the groundworks

Show demolition, new construction and site servicing on the site plan. For the initial project enquiry, discuss the construction task, areas, depths and next decision needed. Demolition, connections and temporary construction conditions are included alongside the new buildings. Known utilities and the respective current plan version are identified.

02

Compare findings

Compare official documents and existing reports. Check official information, aerial photograph analyses and investigation reports for plan version, spatial coverage, depth reference and outstanding questions concerning today’s task. The scope actually documented is decisive. Missing or conflicting information is identified with its relationship to the planned intervention.

03

Supplement historical information

The required state aerial imagery analysis is initiated through the municipal procedure provided locally. If the available findings need supplementation, further historical research is carried out for the specific question. Available aerial imagery, maps and records of use are professionally analysed and related to the present-day construction site. The findings feed into further investigation planning.

04

Clarify dependencies

Coordinate access, construction sections and the investigation sequence on technical grounds. The specialist company selects the technically suitable approach using the investigation objective, grounds for suspicion, ground composition, interference and accessibility. Preliminary services and the permissible activity scope are clarified. Investigation areas and interfaces are coordinated with the construction sequence.

05

Investigate and assess results

Within the agreed and permissible scope, the defined areas or points are investigated using a suitable method. The data collected are recorded with location, depth reference and site conditions. Specialist personnel assess results and anomalies according to the investigation objective, method and interference. A measurement anomaly is not yet identified ordnance. Further clarification required and areas not adequately investigated are identified; local reporting procedures apply if ordnance is found.

06

Record handovers

Hand results and outstanding tasks to the respective subsequent participants. Work performed and its technical assessment are documented in a report with the corresponding site and plan appendices. Methods, areas addressed, depth references and limitations of findings remain traceable. The client and designers compare this status with the next construction phase. Additional specialist works or official steps are identified before the interventions they concern.

Documentation

Pass investigation reports on in full

Findings and their scope

If demolition contractors, site servicing providers and building contractors use different documents, the relevant plans should be clearly identified. Each report must retain clear information on the area and depths investigated. Passing on one results line is insufficient if maps or limitations are needed for its use.

Project responsibilities

FONTANA-EOD’s report documents the commissioned investigation. If construction plans change later, check whether existing results also cover the new interventions. Supplementary investigation questions, remaining limitations and necessary official steps must be clarified before the affected works. A partial report does not establish a general assurance for all areas of a development site.

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.

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
Person in an orange high-visibility vest with a MALÅ survey cart on a meadow.
Person in a high-visibility vest in front of a marked construction area with piles of soil.
Questions from planning

Questions about changes of use in Dortmund

Who is responsible for official explosive ordnance assessment in Dortmund?

Municipal guidance identifies Dortmund’s Ordnungsamt and support from the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg district government. The specific procedure follows the project. Agree official requirements with the responsible authority before the affected groundworks; FONTANA-EOD addresses the agreed permissible private specialist scope.

Is explosive ordnance assessment also needed for projects exempt from the building control procedure?

An explosive ordnance assessment may also be necessary for a project exempt from the building control procedure. Dortmund’s building control guidance also includes such projects in assessment. Requirements for the planned ground intervention must be clarified with the competent authorities using the specific documents.

Why should demolition and new site servicing be considered together?

Both may affect different, partly adjoining ground volumes. A shared site plan makes these connections visible. Existing findings can then be related and unresolved areas identified before separate construction commissions are carried out.

Can a report for a subarea be passed to the next contractor?

Yes, but with its corresponding appendices and identifiable limitations. The next contractor must be able to relate the findings to its own working area. New utilities, greater depths or different construction areas require comparison and, where applicable, further clarification.

What should I do if I find a possible item of ordnance?

Stop work in the affected area and keep your distance. Do not touch or move the object. Notify the police on 110 and follow their instructions. Do not attempt recovery or investigation yourself.

Must temporary connections be considered?

Yes, insofar as they require ground interventions. Their alignments, depths and corresponding excavations are compared with existing results. Temporary use does not change the need for correct identification.

Which documents does the next contractor receive?

The relevant reports with maps, depth references and limitations, and the current plan for its working area. Outstanding questions and further coordination needed are also identified.

Which cost factors and dates must be clarified before commissioning?

The investigation objective, areas and depths, methods, accessibility, necessary preparatory works, assessment and documentation are decisive for the private specialist service. State measures, preparation by construction participants and private commissioning are assigned separately. Scheduling considers the official procedural status, area availability and construction sequence. Specific coordination uses existing documents and outstanding prerequisites.

Project enquiry

Plan a change of use in Dortmund

Show all construction sections together

Send a site plan for demolition, new construction, utilities and access with the proposed depths. Add official communications and complete reports of earlier investigations. Mark known foundations, fill and ground layers still unresolved. Utility and as-built plans and, where applicable, geotechnical and contaminated land documents support description of actual conditions. Identify the findings needed for the next project decision.

Describe handovers and access

Identify the sequence of construction commissions, availability of the areas over time and contacts. Mark connections or peripheral areas not yet clearly assigned to a report. Explicitly state the first proposed ground intervention and areas still inaccessible. Timing should be technically agreed beforehand. New installations may affect investigation. The appropriate sequence permissible within the respective procedure depends on the specific conditions.

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.