Technical map view of the Darmstadt administrative district with Darmstadt marked for explosive ordnance assessment and surveying by FONTANA-EOD

Explosive ordnance surveying in Frankfurt am Main

If you are planning an excavation in Frankfurt am Main, the plans should also show the other groundworks, such as investigation boreholes, shoring, foundations or utility diversions. FONTANA-EOD coordinates the commissioned explosive ordnance investigation with these activities and their sequence. For each intervention, we check which findings are available and which questions remain unresolved.

Groundworks areas

Show the excavation, shoring and other structures on the plan.

Construction sequence

Plan drilling and utility diversions in advance too.

Investigation

Check the existing evidence for each structure.

Discuss the investigation for your excavationExplosive ordnance assessment in Hesse
Assess the construction project

Compare each structure with the ground volume investigated

For your excavation in Frankfurt, excavation work, shoring, foundations and preparatory activities are shown separately. We compare each intervention with the existing findings and agreed investigations. Additional starting points or changed depths remain visible so that the report can be assigned unambiguously to the next work step.

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, notebook and pen.

Use the Frankfurt tender example within its specific scope

The bill of quantities for Goldsteinstraße 238 from 2018 distinguished the initial area survey from further tasks along shoring axes, at well starting points and in the excavation. For your project, the structures and groundworks concerned are likewise described in full. The services specified there are a planning example from that time; your own records and conditions remain decisive for your investigation. The official register of municipalities lists Frankfurt am Main as an independent city in Hesse within the Darmstadt administrative district. For the enquiry, property boundaries, the construction area and individual groundworks are marked on a current plan. Anchors, wells or utility works outside the excavation remain spatially identifiable. Projects in Offenbach, Darmstadt, Wiesbaden or Kassel are coordinated for their own project location and applicable requirements. Existing results are used within the spatial extent of their actual conclusions.

Hesse
Local context

Assess Frankfurt’s wartime history and construction records in context

Assign wartime aerial photographs and the official statement to the construction area

The explosive ordnance clearance service based at Darmstadt Regional Council is responsible for all of Hesse. For an enquiry, the Regional Council requires a precise location description with a suitable plan and marked property boundaries; aerial photograph evaluation can also be requested online. The statement on possible contamination and required work forms the basis for further project coordination.

The Institute of City History’s Frankfurt city chronicle for 1944 records air raids on 18 and 22 March. The entries describe extensive damage across the city. This establishes a historical context for construction planning today; a city chronicle does not establish whether explosive ordnance is present at an individual borehole location.

A property-specific evaluation needs suitable aerial photographs, maps and other available records. Old and current property boundaries, structures and transport areas must be related spatially. Unclear parts of the images remain identifiable as unresolved questions, rather than being replaced by a general statement about the whole city.

Read the Goldsteinstraße example for its stated scope

For the planned office and laboratory building for the municipal drainage service and environmental office at Goldsteinstraße 238, the bill of quantities printed on 27 February 2018 initially specified an area survey. Further necessary surveys during shoring and excavation work were intended to cover the shoring axes, well starting points and excavation area. Your plans should therefore also account for anchor alignments and dewatering wells. Compare their position and depth with the areas actually investigated.

Working together

Distinguish the tasks of client, designers and specialist contractor

Client and operator

The project owner describes the project and provides the existing project records. The operator adds requirements concerning use, access and timing. A coordinating contact agrees their assigned tasks with the other responsible participants. Before commissioning, the record clearly states which information is missing, who will obtain it and which decision the results are intended to support. The project owner provides existing official statements and complete reports with plans. Identify accessible contacts responsible for design and execution. Technical planning describes the excavation, anchors, wells, utilities and preparatory drilling with their positions and depths. Design changes are passed on before the groundworks concerned.

Planning and construction management

Technical planning describes areas, depths, construction methods and changes. Site management coordinates the proposed workflow with the contractors and agreed technical work. Results are assigned to the relevant groundworks. A technical design change is passed on early enough for its effect on the investigation task to be assessed before execution. Boundaries between construction stages remain distinguishable from technical investigation limits. Site management accounts for access, existing utilities, protective measures and agreed hold points. Changes or unexpected findings are passed through the agreed contacts. The specialist contractor documents the commissioned spatial and technical scope, including interference, inaccessible areas and outstanding questions.

Specialist company and competent bodies

The private explosive ordnance contractor carries out the agreed investigation and documentation work. Official requirements and decisions are clarified with the responsible authorities. The documents required for a particular procedure depend on the location and project. The technical report describes the specialist work performed; its conclusions are not presented without review as general authorisation for further groundworks or as an official decision. The explosive ordnance clearance service for Hesse arranges removal and, where necessary, defusing and destruction of explosive ordnance. This state responsibility is considered when planning schedules and notifications. Those responsible clarify the required notification and handover of results according to the specific activity and Hesse’s requirements.

Investigation task

Which specialist task comes next?

Relate the method to the ground volume affected

The conclusion needed depends on the specific groundworks and existing findings. Installations and access affect the technical suitability of the approach. The investigation is therefore coordinated with the actual structure and its surroundings. A general depth figure without this relationship would not adequately describe the task.

Compare specialist services for the ground volume affected

Clarify the remaining areas through targeted further work

If the documented scope does not cover a planned intervention, the unresolved question is spatially defined. Further technical planning builds on this. Results from neighbouring areas can be considered, but are not transferred without review. A supplementary commission receives a specific objective and traceable requirements for execution.

Compare investigation methods
Project types

Record all groundworks for an excavation project spatially

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

Show the excavation volume with additional structures

Alongside the excavation area, show the planned shoring and foundation elements. Their position and depth matter for the technical comparison. A drawn building outline does not necessarily describe the whole ground volume affected. The investigation is therefore related to the work actually planned and its respective areas.

Provide specialist supervision of excavation
Illustration: a person with survey equipment in a marked construction area; an excavator with a drilling attachment stands on the right.

Also record starting points and alignments

For wells, boreholes or other work at individual points, the starting-point location alone may not fully describe the intervention. Provide the planned geometry as far as it is known. Identify missing details. Technical planning can then check which existing conclusions apply and which further investigation might be needed for the relevant volume.

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

Account for preparatory work in its own sequence

A utility or investigation borehole may be planned before the main excavation. Its technical assessment is therefore scheduled for that activity. A later investigation of the excavation does not retrospectively answer the question concerning the earlier work. A coordinated sequence links each intervention with the findings needed beforehand and the working conditions available.

Coordinate the sequence and tasks
Preparation

Prepare the scope and commission together

Establish what needs to be known before commissioning the work

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

Define the specialist task

Coordinate preparatory work with the investigation

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

Clarify preparatory work in the programme

Agree a clear scope and schedule

A sound workflow distinguishes work already clarified technically from outstanding prerequisites. If an area will be accessible only in part, commissioning must take this into account. Handover and assessment of results also need time in the construction sequence. An enquiry therefore does not imply a blanket commitment on dates or cost. Specific coordination connects the described scope with access, documents, execution conditions and the date by which a decision is needed.

Discuss the scope and schedule
Tasks at the site

Plan the excavation, shoring and preparatory work

01

Drilling and utility diversions before excavation

If ground investigation or utility diversions are planned before the main excavation, include them in coordination from the outset. Where groundworks begin before the main excavation, the explosive ordnance question for those interventions must be resolved beforehand. Mark these possible preparatory activities with their position, proposed extent and responsible design participant. For the decision on subsequent work, record which preparatory activities the existing documents cover and which still need clarification. Site management can then relate the work sequence to the conclusions actually available.

02

Position and depth of excavation shoring

Planned excavation shoring may affect different areas and depths from the subsequent excavation. Refer to the associated current plans. An investigation of the excavation area does not automatically answer every question about structures extending beyond it or deeper below it. Before this work, obtain a technical check of whether the existing investigation covers the areas concerned. The evidence should show the investigated area on a suitable plan. If shoring or anchors move, compare their new alignment with these limits. Only this establishes whether supplementary work is needed.

03

Piles, shafts and connecting utilities

Possible piled foundations, shafts or connecting utilities should remain identifiable as separate elements. Even a small additional intervention may raise a different investigation question. Show the structures on the plan and mark areas already investigated and outstanding tasks. A shared property address is not sufficient for this comparison. For every point affected, bring together its location, proposed depth and relationship to existing investigations. Also document points that could not be investigated as planned because of access or interference.

04

Pass on design changes before execution

If a shoring element is moved or a utility rerouted, for example, the parties must receive the revised plans. Whether the existing investigation covers the change must be checked against the actual scope of its conclusions. Completion of a partial investigation does not automatically extend it to new areas. Retain the earlier plan revision and identify the change. This allows later users to trace the basis of a report and the additional decision made for the revised work.

Project documents

Documents that establish the next step

Hand over the results and structural plan together

The documentation identifies the volume actually investigated with its elevation or depth reference. The current structural plan allows comparison with the forthcoming work. Outstanding parts remain visible. A report for the overall project is therefore used within its actual scope, rather than treated as blanket evidence for every structure.

The project title, property, client and plan revision connect the technical records with the construction project. Compile the official statement, historical evaluation and existing reports with their appendices. Identify the area to which each document applies.

Methods, areas covered, interference and access restrictions must be traceable for assessment. The BFR guidance on geophysics explains the importance of surveying conditions. For the excavation, the decisive issue is which conclusions were reached under the actual conditions. Survey anomalies, further investigations and results are assigned so that the work remains traceable. The project file should show which question was answered and which area may remain unresolved. Where clearance work has been commissioned, the clearance record with the associated location and results information forms part of the evidence file.

Identify changes from the version investigated

If anchors, wells or utilities are arranged differently, show the difference from the previous plan. Check whether existing results still apply. Additional needs are described for the area affected. A revised drawing does not automatically extend the earlier investigation scope. Where clearance work was commissioned and carried out, its records and spatial information belong to the same evidence chain. Terms used must match the actual work scope. A summary of results connects the report to the next construction task. Identify areas investigated, relevant depth references, restrictions and coordination still required. Site management must be able to see which work step the documents support. For staged execution, plan revisions and results are updated accordingly. The final records should also remain understandable to later participants who were not involved in the original coordination.

Construction sequence

Coordinate investigation and construction sections

Bring the structures together before commissioning

Provide coordinated plans showing the excavation, shoring, foundations and preparatory interventions. Add the official statement and existing investigation reports. The unresolved explosive ordnance task can then be described for each area. The service scope follows the documented position and accounts for the actual work sequence. For the first discussion, state the exact project address, construction phase and forthcoming groundworks with their position and depth. Mark individual wells, anchors and preparatory boreholes too. State which official statements and plans are already available and which documents are still being obtained. The specialist contractor can then identify outstanding questions and requirements specifically.

Coordinate the construction phase with us

Select the next activity after an investigation

Check which forthcoming groundworks the results cover spatially and technically. Pass the associated documents and restrictions to site management. Other structures remain subject to separate comparison. The next activity is therefore prepared from actual investigation progress, rather than inferred solely from a general completion notice. For staged execution, record when each investigation volume must be accessible and which conclusion is needed before the respective groundworks. The responsible designers and site management compare new structure or point locations with existing results before execution. Additional services are agreed against this specific need for supplementary work.

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

Preliminary investigation, surveying conditions and supplementary surveying

Compare the aerial photograph evaluation with the groundworks plan

The Historical aerial photograph analysis is considered together with other existing findings and the current groundworks plan. A general reference to the city’s history is not sufficient. Use these records to define the question the next investigation should answer for the proposed groundworks.

Access and interference in the survey area

For a Surface survey the accessibility and actual conditions of the construction area must be taken into account. Installations or other interference may limit the conclusions that can be reached. A general survey range cannot therefore be inferred from the size of the excavation; limitations are documented transparently.

Clarify the need for supplementary surveying

Supplementary Surveying may be considered for a technically defined unresolved task. Agree which conclusion is needed for which depth of groundworks and which site requirements apply. An equipment type or the wish for a certificate alone does not adequately describe the investigation commission.

Next steps

Schedule investigations before the respective groundworks

01

Record the plan revision

Compile the official statement and current structural plans. For the initial contact, identify the project address, construction phase and next groundworks. Existing official statements, aerial photograph evaluations and investigation reports are checked with their appendices for plan revision, spatial coverage, depth reference and unresolved questions about the current construction task. Missing records and conflicting boundaries are noted for further coordination.

02

Supplement historical information

Where information is missing, the necessary historical research or aerial photograph evaluation is carried out for the construction area. Available wartime aerial photographs, older maps and files are evaluated against the specific question. Changes to property boundaries, buildings and road alignments are considered. The findings are assigned to the current groundworks plan and used for further investigation planning. Existing information that is already sufficient can continue to be used.

03

Organise the interventions

Distinguish preparatory work, shoring, foundations and excavation spatially. The excavation, shoring, anchors, wells and utility works are organised by the volumes and depths actually affected. Based on the investigation objective, records, access, existing utilities and interference, the specialist contractor determines the suitable method and preparation required. The service scope, responsible parties and handover date are agreed before the intervention concerned.

04

Perform the agreed investigation

Agree outstanding questions and required conditions on a technical basis. The specialist team carries out the agreed survey or technically defined supervision using the agreed method. Survey data and findings are recorded with their spatial reference and the areas actually covered. Access restrictions, interference and changes are documented and coordinated through the designated contacts. Visual observation alone during mechanical excavation is distinguished from technically defined surveying alongside construction.

05

Assess findings by specialists

The recorded data and findings are assessed against the investigation objective, method and actual conditions. A survey anomaly is interpreted technically; detecting it alone does not identify explosive ordnance. Progress, interference, unresolved areas and necessary additions are documented in the report with the associated plans. This supports agreement on the next investigation step or subsequent construction task.

06

Provide results for the next activities

Assign the areas covered and outstanding tasks to the subsequent workflow. The handover includes the report and plans showing methods, volumes and depths investigated, results and limitations. Required submission of results to the explosive ordnance clearance service is coordinated with those responsible. Designers and site management compare the forthcoming groundworks with the documented investigation volume. Supplementary work needed for extra areas, changed well locations or different depths receives technical clarification before execution.

Documentation

Which structures and depths the report covers

Findings and their scope

The records should show which area or intervention was investigated and where the conclusions end. For an excavation project, the connection between the site plan, area covered and structure is particularly important. Inaccessible or unresolved parts remain identifiable as such. State these limits in the summary of results too.

Project responsibilities

The General Provisions for Hesse require documentation of the investigated or cleared areas with a site plan, and submission of the results to the explosive ordnance clearance service. FONTANA-EOD documents the agreed specialist service; official duties remain separate. The BFR Explosive Ordnance Clearance guidelines provide supplementary planning and documentation principles, serving as technical guidance outside their direct scope of application.

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

An excavation area does not describe every lateral intervention

Additional elements may lie outside the excavation footprint shown or affect different depths. Mark them clearly. Comparison with existing results concerns the ground volume actually affected. A limited addition can then receive targeted consideration, without inferring from its inclusion in the same project that it has already been investigated.

Understand investigation reports and their limitations

Distinguish a tendered service from its result

A bill of quantities describes proposed work. Whether it was carried out, and to what extent, follows from the subsequent results records. The two types of document are therefore assessed separately. New groundworks depend on the position supported by traceable evidence, including its spatial limits and restrictions.

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 excavations and explosive ordnance assessment in Frankfurt

Must an early ground investigation borehole also be considered?

Yes. If it forms part of the proposed project, it belongs in preparation as a separate ground intervention. The clarification required depends on existing findings, official requirements and the specific work. A later excavation investigation does not cover it merely because both activities take place on the same property.

Is showing the later excavation on the site plan sufficient?

Not in every case. If shoring, foundations or ancillary work affect additional areas or depths, these should also be identifiable. Only then can the investigation scope be compared with all the groundworks actually planned.

Does a municipal aerial photograph already constitute an explosive ordnance evaluation?

No. Maps and aerial photographs can provide spatial information. A conclusion about explosive ordnance needs suitable information and its technical evaluation. The explosive ordnance clearance service for Hesse describes its research based on Allied wartime aerial photographs and the subsequent official statement for this purpose.

Can the same investigation depth be promised for every excavation?

No. The scope of conclusions required and achievable must be determined from the specific task and actual investigation conditions. A depth without reference to the structure, method, ground conditions and documentation would not be a reliable project specification.

How is a possible explosive ordnance find handled?

Stop the work concerned, keep your distance and do not touch, move or further expose the object. Notify the police immediately on 110. Never take the object to a police station or other official premises yourself. The responsible authorities determine the next steps.

Which documents are needed for an initial discussion?

Send the address and site plan with property and construction area boundaries, the planned interventions with their depths, and existing official statements and investigation reports. Current structural plans or point lists are helpful for shoring, anchors, wells or boreholes. Also state the construction phase, planned start, access conditions and responsible contact.

What determines the work involved and cost of an explosive ordnance investigation?

The work and cost depend on the investigation objective, area or number of points, groundworks depth, available records, access and surveying conditions. Necessary preparation, staged execution and documentation also affect the task. A reliable agreement therefore needs the specific plan revision; the service scope cannot be inferred from property size alone.

What must site management be able to establish from the results report?

The report must transparently connect the areas covered, method used, results and limits of its conclusions. What matters for site management is whether these cover the forthcoming groundworks. Uninvestigated parts and design changes are considered separately; completion of a partial investigation does not automatically cover additional work.

Project enquiry

Explosive ordnance investigation for your Frankfurt construction project

Attach the complete structural plans

Send the current site plan, proposed groundworks with their depths, and existing official statements and investigation reports. Also identify early groundworks and known access restrictions. FONTANA-EOD agrees with you which investigations are needed before the individual activities. Show shoring axes, well locations and early groundworks on the associated plans.

Assign results unambiguously

Also state which earthworks should begin first and which areas are not yet accessible. Necessary preparatory work and handover of results can then be coordinated in good time. Add the construction phase, schedule, utility and site plans, known conditions and the decision needed. Identify missing appendices, unresolved investigation volumes and the associated current plan revision.

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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