Testing & Technical Capabilities

Developing Measurable Information From Physical Evidence

Forensic investigation often begins with observation, but some questions require measurement, testing, comparison, and experimentation.

Dan Rapp Forensic LLC uses field investigation, material sampling, laboratory coordination, custom testing, instrumentation, three-dimensional modeling, and technical data analysis to assist in understanding the performance of building materials and systems.

Where an existing test method does not fully address the question under investigation, case-specific fixtures or testing methods may be developed to obtain comparative and measurable information.

Field Testing & Documentation

Testing begins with accurate documentation of the physical conditions.

Depending upon the matter, this may include:

Dimensional measurements
Photography
Temperature measurements
Moisture-related measurements
Environmental monitoring
LiDAR scanning
Material identification
Destructive investigation
Sampling
Comparative observations

Documenting the condition before, during, and after testing helps preserve the relationship between the physical evidence and the resulting data.

Material Sampling

The reliability of a material investigation often depends upon the quality and representativeness of the samples being evaluated.

Mr. Rapp has experience obtaining material samples from litigated and non-litigated projects and working with laboratories and other experts to develop appropriate destructive-testing programs. His CV also identifies the development of microtome techniques used to reproduce samples for material evaluations.

Sample preparation may involve:

Selection of representative locations
Documentation of sample orientation
Comparison of failed and non-failed material
Dimensional preparation
Sectioning
Controlled removal
Custom sample fixtures
Preservation and labeling

Testing Protocol Development

A testing protocol should establish what is being measured, how the measurement is obtained, what variables are controlled, and how the results can be compared.

Dan Rapp Forensic LLC develops and documents testing procedures where appropriate to the forensic question presented.

Depending upon the investigation, a protocol may address:

Sample preparation
Equipment calibration
Test geometry
Preconditioning
Environmental conditions
Measurement sequence
Repeated testing
Data collection
Photographic documentation
Calculation methods
Acceptance or comparison criteria

Where the investigation crosses into specialized engineering, chemistry, or material-science disciplines, testing can be developed in collaboration with appropriately qualified professionals and laboratories.

Custom Test Equipment

Building the Tool Needed to Investigate the Question

Not every forensic question can be evaluated using commercially available equipment.

Mr. Rapp's hands-on construction and fabrication background allows custom testing fixtures and equipment to be designed around specific materials and physical conditions.

Examples include:

Circumferential Peel Testing Equipment

Equipment developed to perform controlled comparative testing of pipe specimens and material interfaces.

Pipe Ring Pull Tester

A mechanically controlled test system designed to measure force while a prepared pipe-ring specimen is displaced toward a defined geometry.

The equipment permits comparison of specimens under controlled procedures and can be used to investigate differences associated with material location, condition, temperature, or other variables.

Environmental Monitoring Equipment

Custom data-logging equipment can be used to monitor environmental factors such as:

Temperature
Relative humidity
Wood moisture
Substrate moisture-related conditions

This information can provide context for observed building conditions and material performance over time.

Instrumentation & Data Acquisition

Testing equipment can incorporate electronic instrumentation and data collection to improve repeatability and preserve measured results.

Depending upon the application, systems may include:

Load cells
Temperature sensors
Environmental sensors
Digital position measurement
Data loggers
Microcontroller-based instrumentation
Automated measurement recording

The purpose of instrumentation is not simply to create additional data, but to obtain measurements that address a defined forensic question.

Fabrication & Prototype Development

In-house technical development capabilities include:

Manual milling
Lathe work
CNC milling
3D printing
Fixture design
Mechanical prototyping
Sensor integration
Custom sample holders
Test-rig development

These capabilities allow components to be modified and refined during development of a testing procedure.

Laboratory Collaboration

Some investigations require equipment or expertise beyond the scope of field testing.

Dan Rapp Forensic LLC has worked with laboratories and specialized professionals to obtain and evaluate representative material samples and to combine laboratory findings with building-system and field information.

Depending upon the investigation, this collaborative approach may involve:

Materials specialists
Mechanical engineers
Structural engineers
Civil engineers
Specialty consultants
Product manufacturers
Testing laboratories

The objective is to integrate the different disciplines rather than considering laboratory results independently of the conditions in which the product was actually installed and operated.

LiDAR Scanning & Three-Dimensional Modeling

Three-dimensional documentation can provide a more complete record of physical conditions than conventional photographs alone.

Applications may include:

Building geometry
Walking surfaces
Stairs and ramps
Elevation changes
Settlement
Slope
Construction assemblies
Equipment configuration
Demonstrative exhibits

LiDAR data and three-dimensional models can also assist in creating topographical representations and visual explanations of field conditions.

Technical Visualization

Testing and analysis are most valuable when the resulting information can be clearly communicated.

Mr. Rapp's forensic experience includes presentation of complex engineering and construction concepts through visual graphics, three-dimensional models, and mockups intended to make technical information understandable to non-technical audiences.

Technical presentations may include:

Annotated photographs
Diagrams
Graphs
Test results
3D models
Cross-sections
Comparative images
Demonstrative exhibits