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

Explosive ordnance surveying in Unna: Coordinate construction documents

The building application has been submitted, a foundation plan has since changed and the aerial photograph analysis is in another file. These documents must correspond before groundworks. FONTANA-EOD helps clients and design consultancies with construction projects in Unna compare existing knowledge with proposed interventions and describe the specialist task clearly.

Plan revision

Identify the relevant drawing with its date.

Reports

Pass results on with their maps.

Changes

Clarify new areas and depths before construction.

Discuss the project's technical requirementsExplosive ordnance assessment in North Rhine-Westphalia
Assess the construction project

Relate planning and investigation to the same version

For your construction plans in Unna, the intervention plan, existing reports and current changes must correspond. We compare the actual investigation scope with the approaching construction work. Missing appendices and different plan revisions are clarified explicitly before further specialist work.

Project references

Selected project examples

Project site

Connect the site with the specific construction task

Illustrative map of North Rhine-Westphalia with the state coat of arms, a tablet, a white FONTANA-EOD helmet and a notebook.

Keep Unna's regulatory and building procedures traceable

Unna is the administrative centre of the Unna district within the Arnsberg administrative district in North Rhine-Westphalia. Unna's current service information identifies the Ordnungsamt, General Regulatory Law section, for an informal aerial photograph enquiry, along with the state service of the Arnsberg district government. The building control page describes digital applications separately. For your project, the respective documents and responses are brought together with their actual purposes identified.

For specialist preparation, the property, construction area and adjoining working spaces are distinguished on the site plan. An excavation pit may, for example, have a different scope from an access route, building utility connection or lateral retaining works. Assign the relevant report and proposed intervention depth to each area. Works outside the construction property receive their own location information. For a project in the surrounding area, the local contact follows the actual project address. Responses from the Unna procedure remain linked to their property and file reference. Responsible people and the respective documents required are identified for follow-up questions. Further project locations are shown in the regional overview.

For digital applications, Unna's building control page refers to Bauportal.NRW. Private individuals need a BundID; companies may use the business account. Before submission, the appropriate application type, responsible people and any power of attorney required are clarified. Related pages may form one file; individual construction documents are generally supplied separately. Files receive traceable names. The specialist project file records the version submitted and any addition still outstanding. If a further report is added, its purpose and relationship to previous plans are identified. Site management receives the status relevant to its works together with the associated investigation results. Submission confirmation, official response and specialist report remain allocated to their respective procedures.

North Rhine-Westphalia
Local context

Bring historical information and present-day construction plans together

Allocate historical documents and present-day application routes

The City of Unna describes the aerial photograph analysis application as an informal enquiry to the Ordnungsamt. Its building control page separately explains digital submission of building applications through Bauportal.NRW. For construction projects, both procedures are recorded separately with their file references, documents and responses.

The article “Retter der Stadt” in Herbst-Blatt No. 99 of June 2020 reports air raids on Unna's town centre and damage to the town church in the final months of the war. For present-day construction tasks, such historical indications are compared with images from that time and the areas actually used. Subsequent reconstruction, demolition or infrastructure works are considered with their own dates. Available documents must identify which earlier use or ground change is documented for the specific property. Outstanding questions for historical analysis and further investigation are derived from this.

Provide legible files with a clear plan revision

For digital construction documents, the city identifies fully legible files and traceable file names. Individual documents should generally be uploaded separately; related pages may remain in one file. The same care helps specialist coordination: a report whose map is missing, or a plan without an identifiable revision, permits only limited assessment.

The Unna City Archives hold administrative records, maps, plans and photographs, together with other contemporary historical sources. Research brings together the present address and any earlier street or property names. A historical image and current site plan may show different building conditions or area boundaries. Allocation therefore considers identifiable reference points and chronological sequence. Traceably researched findings are linked to existing aerial photograph analyses. Official aerial photograph analysis is arranged through the responsible local office.

Working together

Distinguish the tasks of client, designers and specialist contractor

Client and operator

The client describes the project and provides the available project records. The operator adds requirements for use, access and timing. A coordinating contact brings the parties together; individual tasks remain assigned to the named parties. Before commissioning, it is clearly recorded what information is missing, who will obtain it and what decision the result is intended to prepare.

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 carries out the agreed investigation and documentation work. Requirements and decisions of public authorities are addressed with the responsible bodies. The documents needed for a particular procedure depend on the location and project. The technical report describes the work carried out, including its documented area, depth and scope. Decisions reserved for public authorities are made by those authorities.

For aerial photograph enquiries within the city, Unna's Ordnungsamt, General Regulatory Law section, is the local contact. The state explosive ordnance disposal service at the Arnsberg district government performs its tasks through the official interface. For a permissible private commission, the specific specialist task, authorisations required and result documents needed are clarified. In the event of a find, hazard prevention and further measures are led by the competent authorities. Project participants record which response is needed before each construction phase. Any need for ordnance recovery is coordinated with the permissible task and the competent authorities.

Investigation task

Which specialist task comes next?

Distinguish document quality from specialist needs

Legible files enable processing but do not yet demonstrate a completed investigation. First, it is clarified which findings exist for the proposed intervention and which are missing. Further needs are derived from this. Technical method selection then considers the question and actual conditions at the investigation site.

Assess historical documents

Link the specialist commission to outstanding steps

The agreed scope describes the findings required and underlying plans. Official tasks remain separately identifiable within the process. For private activities in NRW, legal prerequisites and authorisations required are checked. Successful transmission of a document replaces neither an outstanding decision nor a necessary investigation.

Compare investigation methods
Project types

Retain a shared working basis through to site management

Illustration: two people review plans and documents at a table beside a construction vehicle.

Identify the relevant version clearly

The date and plan designation must show which drawing is to be used for the next step. Older versions remain distinguishable as predecessors. When a change occurs, its content is also explained. The parties thus work with the same intervention rather than merely similarly named files.

Document findings and their limitations
Illustration: two people review plans and documents at a table beside a construction vehicle.

Hand over the report and appendices together

Without a map or explanation, specialist findings may lose their spatial reference. Therefore attach all related parts in full. Missing appendices are identified explicitly. Subsequent work can then clarify whether the document covers the proposed area and which limitations must be considered.

Document findings and their limitations
Illustration: two people review plans and documents at a table beside a construction vehicle.

Assign questions to the correct procedure

Record file references and contacts separately for each procedure. A new document must identify the question it answers. Communication is coordinated where several parties are involved. The version actually considered and the response still outstanding thus remain traceable.

Coordinate the sequence and tasks
Preparation

Prepare the scope and commission together

The specialist service is selected according to the specific investigation question and proposed ground intervention. Which activity may be privately commissioned within the specific NRW procedure is clarified separately before agreement.

Establish what needs to be known before commissioning the work

For the Unna commission, the relevant intervention drawing and existing analyses are compiled with their respective appendices. A foundation changed after the building application is identified clearly against earlier versions. This allows it to be established whether documents first need interpretation, additional ground volumes need investigation or assessed findings need further work. The specialist service and result documents required receive a specific scope. The informal aerial photograph enquiry and digital building application retain their own procedures. Transmission of files does not yet describe a completed specialist investigation status.

Define the specialist task

Coordinate preparatory work with the investigation

Before the investigation appointment, actual survey areas, access and available utility information are clarified. Preparation refers to the explicitly identified current plan revision. Preparatory work required depends on the method and site. Additional opening-up work or other ground interventions to create survey access are coordinated technically with the responsible parties and are not undertaken independently. Other trades receive the information needed for their interfaces. Older drawings and changes submitted later are linked so that the construction work actually approaching remains traceable.

Clarify preparatory work in the programme

Agree a clear scope and schedule

The commission records which version of the construction task is addressed and which results already exist for it. Partly accessible areas and missing prerequisites are considered within the scope. Effort and dates depend on actual access, documents and coordination; interpretation and handover are part of the process. Outstanding responses are assigned to their respective procedures. A file receipt confirmation is distinguished from official information and a technical results report. Plan changes are compared with the agreed commission before additional specialist work.

Discuss the scope and schedule
Tasks at the site

What the shared working basis should contain

01

Project and area

Identify the property and draw the proposed groundworks. A building application may encompass more than the area of an earlier explosive ordnance investigation. Therefore check not only whether the address and file reference match but also which subareas the documents actually describe.

02

Depth and height reference

Add proposed depths for the excavation pit, foundation and connections. The reference to ground or design elevation must be identifiable. If two drawings use different elevations, that difference must be clarified before construction. An unchanged building name says nothing about unchanged intervention depths. Ground structure, utilities and other metal installations may affect the method and findings achievable. Specialist planning considers these survey conditions.

03

Complete results reports

Attach maps, appendices and explanations for existing investigations. An email containing abbreviated findings does not replace the report. Comparison requires a traceable record of the works carried out, areas covered and limitations applicable to further planning. Anomalies and possible interfering objects are assessed by specialists. Limitations and outstanding questions remain identified in the survey report.

04

Responsible contacts

Record who maintains current plans and who can answer questions about older reports. This allocation helps when additions are needed because documents are missing or contradictory. The respective specialist leads perform their tasks; official decisions are made by the competent authorities.

Project documents

Documents that establish the next step

Retain findings when planning personnel change

Hand reports over with their associated maps and the relevant design. A short status message is often insufficient for subsequent technical comparison. The limits of existing knowledge remain identifiable. New participants can thus assess what is already evidenced for current construction.

A document overview links file name, date and content to the work area concerned. An aerial photograph analysis includes its associated area boundary and the assessment supplied. For technical investigations, the results report, site plans and documented limitations are supplied together. If an appendix is missing, that item remains explicitly outstanding at handover. The origin of a drawing supplied later also remains identifiable. Subsequent work can thus start from the correct version and obtain the information still needed specifically. The site plan, cadastral parcel and construction area or route must correspond clearly.

Document additions with their effects

If an intervention is relocated or deepened, the change is compared with the previous investigation scope. The resulting assessment belongs in the current project status. An addition must not remain solely in one planning file. The parties affected need the traceable connection between change and result.

At handover of results, areas actually addressed are distinguished from outstanding positions or those with limited interpretability. Site management receives the reports and maps relevant to its construction work. If a route is extended later, the new section is compared with the documented scope. The same applies to additional depth or a changed foundation. The resulting specialist task is assigned a responsible person and linked to the relevant construction phase. A later change of participants takes over this overview together with the complete result documents. In the results file, initial data, survey data, survey results and assessment of findings are assigned to their spatial reference. If clearance was carried out, the associated clearance record supplements the evidence chain. Conclusions for the following construction section are derived from this.

Construction sequence

Coordinate investigation and construction sections

Clarify completeness and relevance before assessment

Collect the relevant plans and existing results with their appendices. Identify missing parts and contradictory information. The specialist task is related to a shared status. Only then can it be determined meaningfully which additional work is needed for the approaching groundworks.

Coordinate the construction phase with us

Pass on the current status before construction

Site management receives the results and limitations relevant to its work area. Later changes are assessed again. Record which documents concern each construction phase. The knowledge actually achieved thus remains traceable even if several companies work on the project consecutively.

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 analysis and other earlier records help establish the spatial basis of a suspected hazard. Images, interpretive capability and area boundaries considered are linked to the present-day intervention drawing. An absence of visible findings is not a technical investigation of the present-day ground. The analysis is brought together with other knowledge and actual construction work. If the plan changed after the enquiry, it is assessed which parts the existing analysis covers. The date of the historical image and date of the current design remain identifiable as different time references.

Understand aerial photograph assessment

Magnetometric survey

Magnetometric methods detect magnetic anomalies. Suitability is assessed using expected objects, ground conditions, interference and the investigation area required. Fences, utilities and existing structures can affect interpretation. Signal strength alone does not identify explosive ordnance. Surveying, assessment and necessary further clarification are linked to the current construction task. The results report shows the area actually addressed and its conditions. A foundation plan changed later is compared with this scope, not merely with the name of the overall area investigated.

Understand the scope of magnetometry

Electromagnetic methods

Electromagnetic investigations may be suitable for certain metallic target objects and site conditions. Selection considers the findings required, accessible survey areas and interfering installations, rather than equipment availability alone. Results receive a spatial reference and information about actual investigation conditions. Whether a supplementary method is needed follows from assessment and the outstanding task. Allocation to the relevant construction design remains documented. The same file name or project name does not, by itself, confirm matching ground volumes.

Understand electromagnetic surveying

Ground-penetrating radar

Under suitable conditions, ground-penetrating radar can provide information about subsurface structures and reflections. Ground conditions, moisture and installations affect interpretability. A reflection is not automatically explosive ordnance; an area without anomalies does not confirm any arbitrary depth. Specialist interpretation and limitations are documented with the commission. Before an existing radar plan prepared for other purposes is used as explosive ordnance evidence, its objective and scope are assessed. Where several file versions exist, the basis actually assessed is assigned to current construction plans.

GPR and limitations

Deep-ground and downhole surveys

For deeper interventions, it may be necessary to assess whether investigation from the surface can provide the findings required or whether another approach is needed. Current positions, depths, reference elevations, borehole layouts and known utilities then form part of preparation. Creation of suitable investigation access is planned by specialists. A standard grid or general depth figure does not replace this task. Results remain bound to the ground volumes actually addressed and method used. If a foundation is relocated or deepened later, the change is checked by specialists before the work concerned.

Prepare deep interventions

Survey during construction

If a necessary advance investigation cannot be completed in full, it is assessed whether a specialist-planned approach accompanying construction is suitable. Investigation, interpretation and communication of findings are linked to the current construction programme. Visual observation of excavated material alone does not replace a necessary survey. Site management receives the allocation of specialist work, new knowledge and outstanding areas to the proposed activities. Revised construction documents are passed on with their revision so that specialist work and actual construction describe the same task.

Agree the approach during construction
Technical assessment

Derive the investigation from the construction task

Read findings together

A historical aerial photograph analysis is considered with the other information available. Its result must be related to the area identified. Further investigation needs depend on the specific project and applicable requirements, not merely on a document already being in the construction file.

For comparison of different drawings, scale, north direction and elevation reference are identified. A site plan shows the proposed area, while a foundation or section drawing clarifies the depths concerned. If the depictions do not agree, the difference is clarified before further work. For a relocated excavation pit, retaining works, slopes and connecting areas are also considered. A shaft added later may occupy ground not previously considered. Specialist planners therefore describe the change using actual working spaces and the findings required for them.

In the digital procedure, the submitted version and later change remain distinguishable. Technical assessment records whether a new drawing fully replaces an older plan or adds only a subarea. Where several specialist designs exist, buildings, drainage and utilities receive the same traceable reference points. An older investigation plan is kept alongside with its own boundaries. The presentation then shows where existing knowledge covers the new plans and which additional question needs work. Those carrying out the works receive the relevant document revision.

Clarify survey conditions on site

For a survey, the actual conditions matter as well as the question. Existing utilities, foundations and access therefore belong in preparation. A digitally legible plan can convey this information; it does not, however, demonstrate that a particular method can provide the findings required everywhere.

Agree steps and handovers

In the clearance plan, necessary investigations and construction steps are coordinated. Record which results are needed before a particular construction phase. A date in the construction programme alone does not confirm that the associated ground intervention has already been sufficiently clarified.

Next steps

Keep changes traceable through to site management

01

Clarify the enquiry, documents and historical information

Initial contact describes the construction project, existing documents and decision required. Reports are brought together with their maps and the current location and depth plans. Missing appendices and contradictory versions are identified. Unresolved historical information is researched and assessed by specialists using suitable records and images. The required official aerial photograph analysis is arranged through the Ordnungsamt. Its findings are assigned to the intervention area actually proposed.

02

Establish the plan revision and investigation method

The plans relevant to further work are identified clearly. A relocated excavation pit, additional shaft or deeper foundation is shown as a specific change. Specialist investigation needs follow the outstanding questions and applicable requirements. Methods, survey scope and preparatory work are determined considering target objects, ground conditions, depth, interference and accessibility. The parties and competent authorities clarify their respective tasks before execution. For additional construction documents requested, the file reference communicated and digital communication route specified by the City of Unna are used. Additions to the explosive ordnance procedure are assigned to the relevant plan revision and outstanding specialist question.

03

Investigate and assess results on technical grounds

Once prerequisites are clarified, the agreed investigation or technically suitable supervision is carried out. Data and observations obtained are interpreted and assessed for their significance to the intervention described. Actually accessible positions and those with limited interpretability remain distinguishable. Changes in site conditions are coordinated with the responsible parties. Assessment identifies usable knowledge, anomalous findings and outstanding questions. The next specialist or official step follows from this.

04

Document results and coordinate the next construction work

Reports and maps document the scope actually addressed, results and their limitations. Site management receives the documents relevant to its area. Before the work concerned, the construction plan and documented findings are compared. Changes to location, depth or construction method are assessed again. The subsequent decision identifies additions or coordination needed for the next construction section. Even if contractors change, the plan revision and investigation scope remain traceable together.

Documentation

Pass on the complete findings

Findings and their scope

Documentation includes the areas actually addressed, works carried out and results derived from them. At handover to another design consultancy, this context should be retained. A single marking without a legend or a sentence without its report can conceal the spatial and technical limits of the findings.

Project responsibilities

FONTANA-EOD addresses the agreed specialist commission. The local regulatory authority and responsible state explosive ordnance disposal service retain their duties. The BFR Kampfmittelräumung provide principles for planning and documentation; they apply directly to federal properties. For other projects, they serve as technical guidance alongside the respective applicable requirements.

Working approach

How FONTANA-EOD works

Document the agreed specialist service clearly

FONTANA-EOD addresses the agreed specialist task for the explicitly identified Unna plan revision. Existing reports and official responses are incorporated with their appendices and limits of findings. Before work begins, accessible areas and results required are coordinated. Changes to plans or site conditions are checked before the work concerned. The report documents the work actually carried out and its limitations. Site management can relate the findings to the current activity and identify clarification still needed. Separate application procedures retain their respective functions.

Discuss the investigation task

The task before the equipment

Method selection starts with the knowledge needed for the current intervention plan. Specialist planning considers existing results and actual conditions. Available equipment or a similarly named neighbouring project does not suffice as the sole basis for selection. Revised drawings are assessed for their effect on the ground volume. The approach is justified for the specifically described task. Merely transmitting a plan does not replace this technical decision.

Keep limitations visible

Inaccessible areas and areas with limited interpretability are identified with their boundaries in the relevant spatial reference. Site management can assign proposed activities and additions still required to them. Information on the whole construction area is supplemented by these outstanding tasks. Planning and construction teams coordinate when a suitable investigation will be possible. Where several report and drawing revisions exist, the ground volume already assessed and the change not yet covered remain identifiable.

Clarify changes before intervening in the ground

A new location, additional depth or different construction method is compared with existing results before the work concerned. Specialist planners receive the revised design with its date and identifiable difference from the previous status. Their response and additions required are assigned to the ground volume concerned. An unchanged file reference or continued file name does not, by itself, confirm an unchanged investigation task. The next activity is prepared using the plan revision actually relevant.

Hand over the report and plan together

Reports and plan appendices are handed over in full with their corresponding drawing revisions. An overview may allocate official procedures, existing results and outstanding tasks. It does not replace the documented investigation scope. Submission confirmation, official response and specialist report retain their respective functions. If site management or companies change, the documents describing the specialist works carried out and their relationship to present proposed construction remain traceable.

Understand the results

Use technical statements for the next decision

A transmission confirmation demonstrates submission

It helps trace submission of a document. The specialist findings already available, by contrast, follow from the corresponding results. Keep these two statuses separate. Further planning can then identify whether a response is merely awaited or usable findings about the intervention already exist.

Understand investigation reports and their limitations

Describe plan changes by location and depth

Also identify the areas, structural elements or depths changed. Technical assessment can then focus on the difference from the previous scope. A traceable change description helps coordination between designers and the construction team. The current design is then recorded with the results applicable to it.

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 documents and application routes in Unna

Where is aerial photograph analysis requested?

According to the City of Unna's service description, an informal enquiry may be submitted to the Ordnungsamt. Use the current contact options identified there and clarify the information needed for your project. Coordinate needs in good time before proposed ground interventions. The state service at the Arnsberg district government supports the local authority within its remit.

Is uploading the plans to the building portal sufficient?

The city's information describes the digital building application and explosive ordnance enquiry separately. Clarify the documents needed for each procedure. Successful file transmission does not, by itself, demonstrate completed explosive ordnance assessment. Specialist comparison requires complete reports with their maps and the current intervention plans.

What happens if the foundation plan changes?

Identify the change and compare the new intervention with existing results. Whether additional steps are needed depends on location, depth and previous coverage. Do not pass revised plans unchecked to the construction team as an already investigated scope. The method used and site interference limit the findings available for additional areas or depths.

Can a short results email replace the report?

Technical assessment requires the complete findings and their spatial reference. Therefore also supply maps, appendices and limitations. An abbreviated message cannot reliably convey this information.

What applies if a suspicious object is found in the ground?

Stop the affected work and keep your distance. Neither touch nor move the object; keep others away. Immediately notify the police on 110 from a safe distance and follow official instructions.

What does confirmation of a digital transmission demonstrate?

Submission of the document concerned. It does not demonstrate a specialist assessment or investigation already completed. The specialist process proceeds from document assessment and required historical analysis through method selection and investigation to assessment and documentation. Results are checked against the plans before follow-on works.

Which factors determine effort and costs?

The method, investigation scope, depth, interference and access determine the effort required. Missing documents or necessary preparation are considered during coordination. For commissioning, agree the specialist service and required result documents with their specific scope. Cost allocation is clarified with the responsible parties under the respective procedure.

How does the evidence status remain clear with several contractors?

Relevant results and limitations are assigned to the respective work areas. Changes and outstanding questions are passed to the parties affected. A revised plan requires a clearly identified version and a description of the location, structural elements or depths changed. Its effect on existing results can then be assessed specifically.

Project enquiry

Prepare the first technical discussion

Identify the relevant version

State the date, plan revision and known changes to proposed interventions. Add the project address, cadastral parcel, official letters and complete analyses with their appendices. The sector overview explains typical interventions and the documents they require.

Keep reports together

Send complete results including maps and appendices. Identify the groundworks approaching first, additional subareas and people responsible for follow-up questions. Also identify proposed access and areas not yet accessible.

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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