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

Explosive ordnance survey for excavations and connections in Gelsenkirchen

Do the existing ordnance documents cover building service connections, shafts and utility routes as well as the excavation? For your construction project in Gelsenkirchen, FONTANA-EOD supports comparison with current plans and preparation and documentation of commissioned investigations. The basis is the affected areas, groundworks and official statement.

Statement

Check requirements for the excavation and connections.

Connections

Mark utility trenches and handover points.

Investigation

Clarify areas, depths and limitations.

Discuss your construction project in GelsenkirchenExplosive ordnance assessment in North Rhine-Westphalia
Assess the construction project

Include connections through to the actual handover point

A building service or sewer connection may extend beyond the construction area initially considered. For your Gelsenkirchen project, we compare the complete groundworks with the official statement and existing reports. Property boundaries and technical investigation boundaries are shown separately. Agree the applications and investigations required before the first ground intervention they affect.

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.

Connect the Gelsenkirchen statement with the complete construction task

The local public order authority summarises the assessment and any recommended measures in a specialist statement. Where referral is required, the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg District Government is involved. For the area drawing, the city explicitly specifies building service and sewer connections. This reference is retained on the project plan without deriving a blanket finding from it. Gelsenkirchen is an independent city in North Rhine-Westphalia and belongs to the Münster administrative district.

An enquiry from Altstadt, Heßler, Bismarck, Schalke or Schalke-Nord, Bulmke-Hüllen, Erle, Buer, Horst, Resse or Ückendorf needs the exact project address and a site plan. Identify the plots, excavation and connection areas affected. For former factory sites, railway or route corridors, existing records of use and the work areas accessible today help. The procedure and scope are related to this information.

FONTANA-EOD has a presence in Wesseling. For projects in Bochum, Essen, Herne, Gladbeck or Marl, identify the respective municipality and specific project location. These neighbouring cities have their own municipal responsibilities. For further projects in the northern Ruhr area, the responsible procedure and specialist task are clarified according to the actual site and proposed groundworks.

North Rhine-Westphalia
Local context

Historical evidence and the local statement

Application and aerial imagery analysis

The city of Gelsenkirchen describes applying for aerial imagery analysis to the local public order authority. If no usable analysis is available, its guidance states that the application is forwarded to the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg District Government. The result and any recommended measures are brought together in a specialist statement.

In its account Bombing nights and reconstruction the city documents the air raids of 6 November 1944. For present-day planning on former mining, steel, energy, factory or storage sites, available use and construction documents are linked with the current groundworks. This also applies to freight stations, shunting areas and industrial sidings, and repurposed industrial and infrastructure sites. Reconstruction, filling and later housing or mixed development may conceal earlier ground and building conditions. The investigation needed follows from the specific records available, results and planned construction task. For former closures, remediation works or new developments, documented earth movements and changes to utility and transport routes are compared with the plans. Slopes and former shaft and plant areas are considered with their location, existing as-built documents and additional specialist requirements.

Building service and sewer connections within the application scope

For project planning, what matters next is which findings relate to which part of the site. The city explicitly also identifies building service and sewer connections. Mark the excavation and connection trench separately with their location and depth. Check whether the existing investigation actually covers both areas. For permits to break the surface, the city describes a limited rule for existing utilities laid or worked on after May 1945: breaking the surface must remain confined exactly to those areas. Agree its applicability to the connection described with the local authority. Additional excavations, lateral extensions or other depths are assigned separately. The city relates its historical depth information to ground level in May 1945; present-day elevation references and known filling or excavation therefore belong in the documents.

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 specialist ordnance contractor carries out the investigation and documentation scope agreed and permissible for the activity. The local public order authority of the city of Gelsenkirchen receives the application and handles the specialist statement with recommended measures. For aerial imagery analyses required and subsequent state measures, the Westfalen-Lippe explosive ordnance disposal service of the Arnsberg District Government is involved. FONTANA-EOD's report documents the specialist service carried out with its purpose, areas treated and remaining limitations. The responsible project parties assign this status to the next construction task and decisions required.

Investigation task

Which specialist task comes next?

Relate the official statement to the connection

Check which areas and tasks the statement actually addresses. Maps and notes on further measures are read together with the current connection plan. A general property designation is insufficient for this allocation. Gelsenkirchen's guidance on building service and sewer connections is therefore considered when drawing the areas.

Assess historical documents

Determine technical needs by section

Location, depth and surrounding conditions may vary along a utility route. Specialist investigation needs are described according to these differences. Before private commissioning, the applicable conditions are checked. A private report does not replace the local statement or a state measure still required.

Compare investigation methods
Project types

Show the entire connection route clearly

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

Plan from the building to the connection point

Show the proposed utility route with shafts, excavations and handover point. The main excavation alone does not describe this task in full. For each section, it is checked which existing findings cover it. One connected utility does not mean that the same conditions or investigation results apply along its entire length. Identify which trade carries out the connection excavation and who receives the associated investigation status before work begins. If the building entry point moves, its new location and depth references are compared with the previous result.

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

Distinguish cadastral plots from groundworks areas

A connection may affect several plots or areas under different management. Both the cadastral allocation and the ground area and volume actually affected are needed. Show working areas and proposed extensions clearly too. A report for a neighbouring property is not transferred to the connection without a specialist basis.

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

Make a changed route visible

If the utility route is shifted later, the old and new plan revisions must be clearly distinguishable. Affected official and technical documents are checked for their scope of findings. The same connection point does not automatically make the changed route an area already considered. Unresolved sections are clarified before construction.

Coordinate the sequence and tasks
Preparation

Prepare the scope and commission together

For commissioning, the investigation objective, existing findings and local procedural status are brought together. Buildings, utility routes and connection excavations remain identifiable with their respective groundworks.

Establish what needs to be known before commissioning the work

The commission first needs to clarify which decision is to be prepared. Is the task an initial assessment of existing documents, investigation of a particular area, or further work on a finding already assessed? These tasks require different evidence. A general wish for safety does not yet describe an executable investigation scope. The enquiry therefore identifies the groundworks, location, depth and findings available. Suitable specialist work and results documents needed are agreed on this basis. For a quotation, provide complete reports with their plan attachments and the current construction design. Identify the findings required for the next contract award. Where building and infrastructure works are commissioned separately, shared connection points and outstanding investigation areas are explicitly assigned.

Define the specialist task

Coordinate preparatory work with the investigation

The access and measurement conditions required are clarified before the appointment. These may include areas to be kept clear, available utility information and coordination with other trades. The preparatory work actually needed follows from the chosen method and site. Surface changes or additional ground interventions are not undertaken independently merely to prepare a measurement. Their sequence is agreed with specialist planning and those responsible. Identify foundations retained, utilities and the areas actually available at the appointment. The type and scope of preparatory services needed are agreed with those responsible. If additional working areas are required, their location is compared with the plans before investigation. Changes to the ground follow the specialist sequence clarified for them.

Clarify preparatory work in the programme

Agree a clear scope and schedule

A reliable programme distinguishes work already clarified on specialist grounds from outstanding prerequisites. If an area will be only partly accessible, this must be considered during commissioning. Handover and assessment of results also need time in the programme. Specific coordination links the described scope with access, documents, construction conditions and the date by which a decision is needed. Pricing considers in particular area, depth, method, accessibility, interpretation and documentation. The city notes that processing at the district government may take several weeks. Prepare the application early with the planned construction start. Delivery of a private service is coordinated separately with the official status, available investigation areas and preparatory work required.

Discuss the scope and schedule
Tasks at the site

Show the excavation and connections on the site plan

01

Building and excavation

Mark the building outline, excavation boundary and proposed foundation elements. If these areas differ, it must remain clear which area an existing investigation covers. A report on the building footprint does not automatically describe the working area farther outside it. Assign the plans and results needed to each building entry point. A shared connection excavation is shown with its full dimensions. If the building plans change later, new boundary areas can then be identified and professionally clarified before the affected work.

02

Building service and sewer connections

List the planned connection routes through to their handover points. Trenches, shafts and crossings may lie outside the construction site initially considered. Before commissioning, clarify whether these additional groundworks also need investigation and are covered by the commission. Construction stages with temporary utilities or trenches open in sections can also be shown. Record which area will be available at the proposed investigation appointment. If the route shifts, the changed areas are visibly incorporated into the updated plans.

03

Several cadastral plots

If a project affects several properties, link the plot details with a clearly marked groundworks area. For subsequent interpretation, it must be traceable whether findings concern the entire area applied for or defined investigation sections.

04

Extensions during construction

If a utility route changes or an additional shaft is added, for example, compare the change with the previous evidence scope. A newly added area is not automatically covered by the previous report. Use the documents to clarify with the competent authorities which further steps are required.

Project documents

Documents that establish the next step

Coordinate utility and building plans

Those involved need a common representation of the connection route. Identify who plans each section and which results are already available. Differences between plan revisions are resolved before the service scope is defined. Bringing the information together provides orientation; the complete statements and technical attachments remain the definitive basis. For further use, the plan designation, date and plot reference are carried forward. Specialist planning can then compare a changed connection point with the documented investigation area. The complete report and its attachments remain accessible to those responsible for building and civil engineering work.

Pass documents across property boundaries

When the responsible contractor or party managing an area changes, the connection between documents must not be lost. The relevant section and its documented limitations are handed over. Where clearance work has been carried out, the clearance record, including the property sections treated, actual clearance scope and results, is handed over with the associated plans. A boundary of responsibility is not an investigation boundary. Conversely, a report may cover only part of a construction task grouped together organisationally. Alongside the assessment, the areas treated, depths and limitations are passed on. Identify inaccessible parts of the site as outstanding tasks. When work resumes, the installations now planned and current construction sequence are compared with these results.

Construction sequence

Coordinate investigation and construction sections

Before submitting documents

Draw the complete groundworks, including connection areas. For larger areas or routes, the city's additional guidance on digital drawings must be observed. The plan should identify the actual task. Analyses and statements already available are included with their respective limitations.

Coordinate the construction phase with us

Before handover to utility contractors

Assign the results to the current construction plan. Check whether shafts, handover points and later changes are also covered. Outstanding questions are clarified before the affected work. A general notification about the main excavation does not replace a traceable document handover for the entire connection.

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 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

Which investigation is required for the planned groundworks

Aerial imagery analysis and official notes

A historical aerial photograph analysis provides information on the earlier situation and possible indications of suspected ordnance. Together with the official statement, it is checked which areas and groundworks are covered. Indications concerning individual points and those concerning larger areas must not be equated without specialist assessment.

Areas and measurement conditions

Whether a surface survey fits the task depends, among other things, on its objective, interference and accessibility. Utilities, installations or covered parts of the site must be identified as conditions affecting the work. The subsequent report must show where substantiated findings were possible and where limitations remain.

Responsibilities for further investigations

Private ordnance surveying and other commissioned specialist services do not replace a decision by the competent authorities. Limited conditions apply to private downhole detection and explosive ordnance clearance during construction in North Rhine-Westphalia. An unresolved section must not be treated as complete merely through visual observation during excavation.

Next steps

Preparation and handover of the investigation

01

Mark the groundworks

Mark the excavation, foundations and connections with their elevations and depths. The initial project enquiry discusses the construction task, areas, depths and next decision required. In addition to new buildings, demolition, connections and temporary construction stages are included. Known utilities and the respective current plan revision are assigned.

02

Assign the documents

Compare the application area, statement and existing investigation plans. Responses, aerial imagery analyses and investigation reports are checked for plan revision, spatial coverage, depth reference and outstanding questions concerning the current task. The scope actually documented is decisive. Missing or contradictory information is identified in relation to the planned groundworks.

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

Define tasks

Agree the investigation scope, responsibilities and unresolved areas before construction. The specialist contractor selects the technically suitable approach according to the investigation objective, basis for suspected ordnance, ground composition, interference and accessibility. Preparatory services and the permissible scope of activity 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

Hand over results

Pass the report and site plan with remaining limitations to the construction planning team. The work carried out and its specialist assessment are documented in a report with associated site and plan attachments. Methods, areas investigated, depth references and limitations remain traceable. The client and planning team compare this status with the next construction phase. Additional specialist work or official steps are identified before the groundworks they affect.

Documentation

What site management must be able to identify from the evidence

Findings and their scope

The report must show which areas were investigated using which method and to what depth. This includes elevation references and parts of the site not yet fully addressed. This information enables assessment of whether a later change to the plans is covered by the existing result.

Project responsibilities

FONTANA-EOD documents the investigation commissioned and its results. Official statements and decisions required are recorded separately. Outside their direct scope relating to federal property, the BFR Kampfmittelräumung serve as specialist guidance; they do not replace a local determination for the specific project.

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

A connection is more than a line

For the actual ground intervention, excavations, shafts, working areas and volumes, and depths matter alongside the route. These details are compared with existing results. A line on an overview map may help orientation but does not always describe the full ground area and volume affected.

Understand investigation reports and their limitations

The statement and technical report serve different purposes

The official assessment and documentation of a specific investigation are considered together. Both retain their respective scope and limitations. Passing on a private report does not replace official processing required. Conversely, a general statement is not automatically evidence that a technical investigation has been carried out.

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
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 ordnance investigation in Gelsenkirchen

Which documents does the city specify for the application?

The city specifies, among other things, applicant details, property and plot information, a description of the ground intervention, planned construction start and a map with the area marked. For large areas or routes, it additionally refers to a digital area drawing. Check the current requirements on the linked city webpage.

Must building service and sewer connections also be considered?

Include the proposed connections in the project description. Whether existing evidence covers them depends on the areas and depths investigated and the report findings. The city of Gelsenkirchen explicitly identifies areas for building service and sewer connections.

Is an investigation of a neighbouring property sufficient?

A neighbouring report may provide information for specialist assessment. It does not replace evidence relating to your own groundworks area. Location, investigation depth, method used and the limitations described in the report remain decisive.

Can FONTANA-EOD replace the official statement?

No. FONTANA-EOD provides the specialist services agreed. This does not replace the official statement or the duties of the local public order authority and state explosive ordnance disposal service.

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

Stop work in the affected area, do not touch or move the object, and keep your distance. Notify the police by calling 110. Further securing and assessment belong with the competent authorities.

Must a relocated connection route be compared again?

Yes. The new route and its depth are compared with existing area and investigation information. The same handover point does not establish that the changed route is covered too.

Why is a single line on the site plan not always sufficient?

It may show neither excavations nor shafts and working areas. Specialist allocation needs the groundworks actually proposed to be understandable.

Which costs and lead times need clarification before commissioning?

The city describes aerial imagery analyses, measurement data acquisition and state recovery work as free of administrative fees for applicants. Obtaining maps and the necessary preparatory, accompanying or follow-up measures are assigned separately. The scope of a private specialist commission is also agreed individually. Area, depth, method, accessibility, interpretation and documentation matter for this. Official processing may take several weeks; coordinate the current status and investigation conditions with the proposed construction phase.

Project enquiry

Have the excavation and connection areas assessed together

Show the full connection

Send the route, handover point, shafts, excavations and depths with the current plan revision. The city needs applicant details, the project address, cadastral district, section and plots, a short description of the ground intervention and planned construction start. Include the application area clearly outlined in red on an appropriate map extract; for large areas or routes, the city additionally specifies a digital area drawing as a shapefile. Identify current access, utilities and parts of the site not yet available.

Include the existing statement

Send official and technical documents in full and identify later changes. The subsequent utility contractor receives the current construction plan with the associated complete statements and reports. Documented limitations and unresolved areas remain explicitly identifiable. State which earthworks begin first and which findings are needed for them. The site plan, plots, construction phase, depths, utility plans and existing ground investigation documents are assigned to the areas commissioned.

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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