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Portable Particulate Detection Device

Final Report Summary - PORPARDET (Portable Particulate Detection Device)

Executive summary:

PORPARDET was an REA supported collaborative project between EU companies and research organisations working together with the objective of developing novel portable asbestos detection systems using innovative concentrating and analytical methods. Specifically two devices were targeted.

- An early warning hand-held device with an alarm
- A portable device for rapid on-site quantitative analysis

Project Context and Objectives:

The context of the project is routed in the widespread and historical use of asbestos as an insulating material in the construction and industrial sector. The first accounts of severe respiratory disease in workers routinely working with asbestos were published in England (1898, 1906), France (1907) and Italy (1908). Regulations for exposure to asbestos were introduced about a hundred years ago in order to reduce incidence of asbestosis and malignant tumours. Standards have been progressively tightened in line with growing awareness of the dangers.

The EU Directive 2003/18/EC states that buildings are normally required to be surveyed, and any items containing asbestos labelled and recorded to allow for asbestos removal to be 'managed' safely. Some demolition contractors across Europe do not have the expertise to 'manage' audits satisfactorily, or without risk to workers and the environment. Workers need to know quickly when they are working with asbestos so that they can take the necessary precautions, without suffering the disadvantages of having to continuously use hand-held protective equipment at all times.

The scientific and technical objectives of the project were:

To develop a hand-held asbestos detection system to provide early warning of the presence of asbestos particulates in the atmosphere. The optical properties of asbestos fibres were to be utilised to provide an early warning physical alarm of their presence. The device detector was to analyse the optical pattern generated under directional polarised light conditions, and hence show the presence of specific asbestos fibres of complex chemistry, eg blue asbestos. A miniature diffraction based optical detector was to obtain the spectra from specific molecular arrangements that can allow particles to be differentiated. A novel concentration system draws the air through a removable cartridge containing the particulates in a way that also provides a time exposure record. This device was initially aimed at having a weight less than 1.0kg be able to qualitatively identify asbestos fibres in the presence of other airborne particulates, and be powered by rechargeable battery with an operating capability of at least 8 hours. It will incorporate both an audible and visual warning system. A target specification was to be available by month 3 (Milestone 1) and an initial manufacturing specification will be drawn up by month 26 (Milestone 2). A working prototype device was aimed at being available by month 27 (Milestone 3)

The social objectives onwards, from the end of the project were:

To minimise exposure to asbestos in disaster situations, building renovation and during ship and train decommissioning and recycling.

To provide easy and accurate testing to help reduce the 6,700 European deaths each year from asbestos related illness (Eurostat, 1995).

To promote and increase the testing for asbestos by reducing the time and cost of testing.
To provide historical data of asbestos contamination on sites.

The environmental objectives of the project were:

To provide low cost, early detection and monitoring of dangerous asbestos fibres, thereby minimising release of dangerous fibres into the atmosphere.

Project Results:

Main Scientific and Technical Results

Since the time of initial specification (Work Package 1) and through the continuous development of the project some aspects of the specification have been superseded. The main change has been related to the mode of operation of the hand held device. Many technical aspects have also evolved to simplify the laser scanning system. However, the processing and control circuits developed in this project remain at the cutting edge of technical feasibility. In a divergence from original planed activity the analytical system development initially preceded the hand held unit. The reasons for this are that many control systems had to be proved on larger scale circuit boards, to establish cost effective technology. Subsequent redesign of these control circuits by GSPK allowed the use surface mount technology to down size the circuits boards. These smaller circuits were then appropriate for developing and use in the hand held system.

The original hand held specification is given below

Outline Concept:

Size: A hand held device;
Weight: 1000 g or less;
Shape: A meter or pistol grip format;

System Usage:

The device consists of a handheld main body containing all the functional parts. A probe on the front of the device was to be used to scrape or penetrate materials thereby breaking off fibres which are then drawn into the device under vacuum. The fibres undergo analysis and the device provides a warning if asbestos is detected. The device must be thermally stable and acclimatised to the test environment, therefore a 1 hour stabilisation period is recommended prior to testing to allow for thermal equalisation.

Alarm functions will be used to indicate the following:

Internal calibration;
Low battery alarm;
Battery overcharge alarm;
Battery over temperature;
Loud alarm on detection of asbestos;
Alarm test button;
Alarm to replace blocked filter medium or tube blockage;
Each function has an appropriate LED of different colour and or position;
Visual indication of battery condition, i.e. charge remaining when switched on and while being recharged.

On activation, the device undergoes self diagnosis (user is given a wait message) comprising:

Thermal comparison of internal to external temperature, unit will only function if these are in the same range;
Laser temperature compensation is carried out;
The device executes systems checks against a calibrated internal birefringent sample;
If all OK - the user is asked to proceed with sample capture;

The original analytical system specification is given below:

Outline Concept:

Size: A large brief case / small suitcase sized device;
Weight: 20kg or less;
Shape: No particular format so long as contained within a suitably robust case;

System Usage:

The device is contained in a case, which on opening, gives access to the functional mechanisms. The device is mains powered 110 / 240 V switch selectable, via a UK square 3 pin 13A plug (no internal back up supply). Asbestos detection takes place by 2 modes:

Mode 1 - A previously contaminated filter from the hand held version is manually loaded into the sensing bay. Detection takes place and the output is displayed on an internal screen. The output is quantitative, determining the asbestos type, fibre size and quantity of asbestos fibres present.

Mode 2 - Used as an air monitoring system the device determines the number of asbestos particles of a particular size detected per unit time. The device displays quantitatively the asbestos type, fibre size, the rate of fibre capture per unit volume and total asbestos fibre count at test termination. Following design changes rate counting will no longer be available.

Alarm functions will be used to indicate the following:

Internal calibration;
A loud alarm on detection of asbestos;
Alarm test button;
Alarm to replace blocked filter medium or tube blockage;
Each function has an appropriate LED or warning on an LCD screen;

On activation the device undergoes self diagnosis (user is given a wait message) comprising:

Thermal comparison of internal to external temperature, the device will only function if they are the same;
Laser temperature compensation is carried out;
The device executes systems checks against a calibrated internal birefringent sample;
If all OK - the user is asked to proceed with sample capture;

Pre-filter particle detection: A small percentage of the laser light is to be used to detect particles entering the device before adhering to the filter system. By using a back scatter method in conjunction with a photo detector, the device will give the user a positive indication that a good reading is underway. If there is no detection, a warning will ask to check for blockage and reacquire a sample. An LED light or similar display on an LCD panel will indicate that a test is underway. Particles are received at the filter whether asbestos or not. Part of the laser beam is again split and transmitted across the filter.

Activation sequence as follows:

Start test;
Warm up;
Confirm OK;
Scan filter - check for filter presence and contamination;
Acquire sample;
Check back scatter from admitted particles;
Confirm test proceeding OK otherwise retest;
Scan particles at filter;
Test for birefringence and count per unit time - repeat loop;
Test for filter blockage - repeat loop;
If filter blocked - warning alarm;
End test after preset time or filter blockage;

Specification simplification:
One of the main barriers to commercial success for this project seemed to be contamination of the detector bay or sensing area. The partners found a solution to this by separating the pump and filter functionality from the laser detector. The separation simplified the design of all the devices and kept contamination issues away from the laser systems. Since the laser systems no longer contain a sensing bay/area, it is now a sealed unit with an optical window for detection. The pump unit separation gave rise to other differences from the original specification in that there are no tubes or blockage issues, therefore there are no requirements to detect these, resulting in their removal from the laser system specification.

Laser system:

The original specification called for as below has been maintained:

Laser Specification;
Laser type: Semiconductor laser diode;
Wavelength: less than630 nm;
Power: up to 500 mW;
Light type: Polarised;
Laser temperature - 'Thermo-electrically' controlled to ± 0.1 or 0.01°C (system dependant);

Filter Capture System:
The filter capture system was designed to the following specification:

Filter type: MPPS 99.95% efficient;
Filter format: Rotating disc;
Filter size: Nominal 60mm diameter;
Filter life expectancy: 2 years maximum;
Required flow rate up to: 2.8 l/min;
Mode of operation: 12 spots on a rotating disc;
Filter contamination: Do not expose filter to atmosphere until ready to use (lid or caddy system);
Filter safe handling: Do not bend and store in recommended conditions as on packaging;
Filter disposal: If no detection warning, filter can be disposed of in regular waste / incinerated or stored for test records;
Filter health and safety: Filter will be contaminated with asbestos if warning is present. Cover the filter pad with dielectric tape to preserve sample for further testing (also eliminates cross contamination risks);
Filter endurance in operation: No continuous operation, point and shoot device;
Filter sell price: 4 to 6 EUROS per disc;
Filter housing: May require a protective carousel - additional specification required later at additional cost;

Filter Pump Specification:

Pump type: Rotary Vane;
Manufacturer: Thomas;
Flow rate: 3.2 l/min;
Max pressure: 600 mbar;
Max vacuum: -500 mbar;
Motor type: Permanent magnet;
Nominal voltage: 6V DC;
Max current: 1.35 A;
Protection class: IP20;
Operation temperature: 0 to 40 °C;
Nominal weight: 100 g;

Following the specification of the devices, the key components were developed.

Within Work Package 2 a bench top system based on the design and specifications developed in Work Package 1 was produced at Applied Materials Technologies Limited. The components used within this phase of the project were commercially available products that allowed the demonstration of the proof-of-principle at the laboratory scale on an optical bench.

The video (PORPARDET/222590/D2 Video) showed the assembled bench top facility in place at the laboratories of Applied Materials Technologies Limited. The video shows each of the modules in the system diagram, and illustrates the proof-of-principle in that a birefringent material can be identified. The polarising rotation at +/- 90° gave good signal extinction, however a better response was obtained for movement of 0 to 20°. It was suggested the detector should be located at 15° off axis.

The integrated approach allowed the mounting of the developed scanning elements with the optical sled developed in Work Package 3 resulting in the scanning analytical system.

The time taken by the scanning system to view all 36 million point spots on the filter paper, when the beam size was reduced to 5 microns was calculated to be 8 minutes. Applied Materials Technology Limited investigated faster scanning systems which could scan the filter in a maximum of three seconds, however this posed problems with the system's electronics and so the modification was not incorporated.

Work package 3 was the "Optical system design and proof of performance of bench top detection systems". The approach followed to achieve this was:

A preliminary study and design was for an optical system that can conform to the requirements of the project objectives;
Fabrication of a preliminary bench-top assembly is created, where the proof of concept, practical investigation is performed;
Optimisation of the design for the handheld unit;
Construction of the miniaturised system assembly according to the optimised design, ready for integration into the handheld assembly.

The illumination system is a critical part of the device. In order to obtain a positive detection, a few conditions have to be met:

It is important to obtain on the sample a laser spot with a size comparable to the size of asbestos fibres we aim to detect (approximately 5µm).

The spot size, shape and direction of illumination must remain stable on the surface of the filter during the scanning, regardless of the position or area of the sample that is being scanned.

Laser radiation parameters must be constant for the duration of the scan
Laser intensity should be strong enough to ensure a good reception of the reflected signal and small signal to noise ratio.

The illumination system is composed of a diode laser and optic beam manipulation system in an attempt to create a compact, cost effective and energy efficient device.

The illumination system had two primary activities, Applied Materials led the task to develop a reliable laser diode to meet the required characteristics, the Optoelectronica team led the task to design and build an optical system for the laser beam manipulation. GSPK designed the electrical and electronic interface of the detection system with the control electronics of the handheld prototype. TWI provided input with relevant expertise in the areas of system design and miniaturisation, electronics, photonics and mechanical component design.

Optical Design and Bench-top System:

During the development of the diode laser Optoelectronica concentrated on the development of a preliminary optical design to ensure a constant beam waist and a necessary depth of focus on the entire filter probe surface to be scanned. In order to achieve this performance, a bench setup using a HeNe laser was established. The preliminary optical design was tested to determine whether the beam could be reduced to a 5 micron diameter. To determine this a range of diffraction gratings were used as targets and this allowed the beam size to be inferred since the target diameter was too small to be accurately measured even for the high quality beam profiling equipment available within the partnership.( a Spiricon COHU 4812).

When illuminated with the optically manipulated beam it was observed that the reflected grating steps started to disappear as the beam diameter was reduced. As the diameter equalled half the grating spacing the beam ceased diffracting and was observed as a simple round spot.

A second series of tests with gratings was undertaken since gratings have some optical similarities with asbestos fibres. The experiment therefore was about simulating an asbestos sample using diffraction gratings.

The preliminary optical design was shown to provide all the necessary characteristics and so was concluded as being the basis for optimisation. The design contained a number of optical components. The laser was mounted at the entrance of the beam expander, and aligned with the optical axis of the expander. The aperture of the polarisation rotator allows procession of a 10mm expanded beam. The rotator can be fixed in front of the expander. To gain more space the galvo scanner could be mounted closely to the rest of the setup. After the scanner the beam will be deflected at the entrance of the F-theta lens. The distance between these two components can be calculated considering the scanning angle.

The photodetector was at 15° from the optical axis on the F-theta lens.

The purpose of the optical project was to scan a 30x30mm sample with a beam focused at 5um. The commercial objective was to achieve a 5µm waist according to its specifications chart. To obtain this performance we needed to ensure a 10mm beam diameter at the entrance pupil of the objective. It was possible to achieve this target using a beam expander. Since the Galvo-scanner can deflect a 10mm beam, it was established as feasible to F-theta objective at its recommended specifications.

On achievement of the optical design it was necessary to incorporate the small diode laser, rather than the expensive, high quality, large and heavy HeNe laser, Fabrication of the diode laser proved to be the critical pathway for the entire project. Rather than an iterative development using established and available assembly methods, as originally envisaged, a fundamental technical challenge was identified. The successful resolution to this was brought about by the design and build of a unique facility, a micro-lenser, this is described later.

Once the diode laser had been successfully developed it was incorporated into the test bed for the final design refinement and assembly of the optical sled for the prototype manufacture. The main requirement for the optical system was to obtain the smallest spot diameter of the focused beam on the sample having a rectangular form of 30mmx30mm, which is dictated by the size of the filter, which is in turn dictated by the number of measurements to be taken.

For a 30mm wide filter analysis with a 5µm spot size requires 6 000 individual measurement to be taken to allow the identification of an asbestos fibre at any point. With the filter paper being 30mm long this means that 36 000 000 measurements need to be taken to ensure the entire surface area of the filter is examined.

The optical setup was mounted with high precision. The mounts are integrally designed for this project and were manufactured and assembled at by Optoelectronica. The mounts are capable of fine tuning to ensure the necessary precision for the optical alignment.

This provided a sled on which all the necessary components were placed. This sled was then the a key part of the prototype assembly which occurred in work package 6.

The micro-lensing system:

The requirement for the micro-lenser was the result of a stringent requirement for precision and repeatability in positioning of the "micro lens" onto the laser diode. The result of meeting these criteria allowed the accurate and reproducible assembly of a laser diode that could then be integrated into the final assembly of the asbestos detector. This critical and essential component could then be aligned with the the other optical components within the system.

The central purpose of the micro-lenser was to allow the preliminary lens to be positioned directly onto the laser diode.

The original micro-lenser was a bench mounted arrangement using cameras, an optical microscope and a series of simple vernier driven moving stage. The laser and its power supply were coupled to provide power to allow the output of the lensed laser to be examined using a cathode ray oscilloscope. The need for manual adjustment on the original lenser induced vibration in the system and made simultaneous adjustment and viewing the resulting beam data very difficult. Operator exposure to the laser beam was also potentially hazardous in this arrangement.

The laser diode is a small, less than1mm planar device, that generates a beam of single wavelength light. Due to this structure, the laser light that is emitted has two axes, known as the fast and slow axes. Achieving a circular beam of laser light from such a diode requires a lens to be placed accurately and precisely in front of the lasing face of the diode. The lens must have the appropriate characteristics to ensure that the fast and slow axes are focused separately and in such a manner to allow an homogeneous cross-section of the light to result. This light will still diverge as it moves away from the diode, but the fast and slow axes will diverge at the same rate. Therefore, Positioning of the lens is central to achieving a controlled and predictable resultant beam.

Given the size and scale of the diode and micro-lens, an alternative machine was required to fulfil the technical specifications for lensing. Such a machine needed to be able to move the lens relative to the diode by incremenst of 0.3µm. Project partners T.W.I. GSPK and Applied Materials Technology Ltd, were able to identify and acquire a redundant optical fibre positioner. The partners then undertook a process over renovation, overhaul and upgrading to allow the positioner to be used within the PORPARDET project.

This activity was essential to the success of the project since:

Micro-positioners are not readily available;
A suitable micro-positioner would only be made to order;
The key items within micro-positioners are piezoelectric worm-motors. Typically, these motors cost in excess of 6000 EUROS, for full 6-axis positioning and control, together with rotation and yaw control, eight motors are required;
The redundant positioner was acquired at no cost, and had eight fully functional worm motors present;
The redundant positioner came with no circuit diagrams;
No operational instructions were available for the positioner;
A number of key items such as processing units, motherboards and even the remote control were not available and had to be designed and built by the project partners.

The benefits to the project of building the micro-lensing facility were:

The micro-lenser allows laser diodes to be manufactured accurately, reproducibly with controlled repeatable beam characteristics;
To purchase this unit would not have been possible in the scope of the project budget and would have cost significantly more than 150,000 EUROS;
The reverse engineering, design and assembly involved meant that the micro-lenser had the scope of a project in itself;
The micro-lensing system has capability for future work/ projects for the project partners;
There is scope for further refining the micro-lensing system specifications and capabilities.

Therefore, the facility allowed accurately lensed laser diode to be manufactured, these were incorporated into the optical sled and were determined to have the necessary characteristics required by the device specification. Without this facility diodes with the necessary beam characteristics could not have been manufactured.

The work performed under WP4 was to develop an image capture and software interpretation system. This was divided into four main tasks leading to an integrated and validated system.

The original task titles were:
Task 1. Design build and trial image capture camera;
Task 2. Develop and test image capture software;
Task 3. Trail hardware and software under different illumination conditions using filter systems;
Task 4. Calibrate system on test samples;

These tasks were translated to the following through the course of the project;

Image Processing Hardware Development: This task aimed to design, fabricate, assemble and extensively test a novel compact, low-powered processing unit which can accommodate high processing power with minimal power consumption.

Asbestos Counting Algorithm Development: This task was concentrated in the development of advanced image processing algorithms for asbestos counting taking in account fibre size and polarisation.

Algorithm training and validation testing: This task was focused on the extensive training of the asbestos detection and counting algorithm using real asbestos images and relative counting results performed in the lab by expert scientists. The aim of this work was to optimise the counting accuracy of the software and perform extensive testing and comparison of the algorithm performance with the traditional method of manual fibre counting in the lab.

Asbestos counting algorithm optimisation for porting on the Field Gate Programmable Array (FPGA) processing unit: This task involves the optimisation of the algorithm to be executed on the FPGA. The algorithm optimisation involved the breakdown to individual sub-processes which could run in parallel on the FPGA. This approach significantly contributed to the reduction of respond time while keeping power requirements very low.

The combination of the outcomes of the above subtasks produced a standalone processing unit which will be integrated with the device electronics for image acquisition and displaying of the results. The hardware that was produced in this WP along with the associated counting software will become the main processing unit of the whole system.

It was decided to design one powerful compact processing unit, to be used in both the hand held and analytical systems. Extended effort was required to ensure a small physical size whilst allowing a complex and highly powerful processing unit able to read and process very large images (6k x 6k pixels) in real time. The additional effort required to achieve this is justified by the enhanced functionality, reduced integration requirements and lower project production costs as the same hardware will be included in both devices.

The final FPGA processing board designed and developed by SignalGeneriX has the following characteristics:

Low power operation;
Significant processing power;
Significant Memory on-board;
SD card offers additional memory;
Easy Expandability and Connectivity;
Mains and Battery operation option;
Compact Size;
10 layer PCB.

Asbestos Counting Algorithmic Development: This task was concentrated in the development of advanced image processing algorithms for asbestos counting taking in account fibre size and orientation. In the absence of a vast quantity of real asbestos pictures and the planned delay in finalising the optical image grabbing system, CUT in collaboration with SignalGeneriX have developed advanced optical image simulation software.

The fibre detection and counting system boasts graphical user interface making it practical and simple to use and provides three methods of estimation:

Manual estimation;
Early detection;
Analytical method.

A safe validation method was developed that automatically generates binary images with random number of fibres in the range of 0~500. In the binary images, the background is represented by pixels having values equal to zero, while the fibres are represented by pixels having values equal to one. The created images have random dimensions that satisfy the aspect ratio (length/width greater than 3:1). The size and shape of representative asbestos fibres images was achieved with collaboration from the Nofer Institute who provided specimen fibre images. The image generation software was used to validate the capabilities of the fibre counting and analysis software.

The operation of the software is user-friendly and intuitive. The binary image is created initially with a random number of fibres based on the user choice. Next, the user estimates the number of fibres manually and chooses between early estimation and analytical method for automated fibres estimation. Finally, the user can check the results clear the image and start the process from the beginning.

In the early estimation method, the image is written in .txt file and then the data is read serially from this file. In order to estimate the total number of fibres, the system calculates the total number of white pixels and the average number of pixels per fibre. The analytical method is based on the well known feature extraction technique, Hough Transform. The technique finds lines in an image using a procedure carried out in a parameter space from which object candidates are obtained as local maxima.

The performance of the system was based on 100 different experiments provided by 5 different users. Although the overlapping fibres influence the estimation procedure, the system accuracy is satisfactory with 90% accuracy on early estimation and 95% using the analytical method.

Algorithm training and validation testing: This task was focused on the extensive training of the asbestos detection and counting algorithm using real asbestos images and relative counting results performed in the lab by expert scientists. The aim of this work was to optimise the counting accuracy of the software and perform extensive testing and comparison of the algorithm performance with the traditional method of manual fibre counting in the lab. Extensive testing showed an accuracy of 95% +/- 2 fibres which is considered extremely accurate for this application.

Asbestos counting algorithm optimisation for porting on the FPGA processing unit: This task involves the optimisation of the algorithm so as execute it on the FPGA. The algorithm optimisation involved the breakdown to individual sub-processes which could run in parallel on the FPGA. This approach significantly contributed to the reduced the response time while keeping power requirements very low.

Work Package 4 has achieved all the objectives possible within the status of the project to date. Specifically, the image processing hardware has been developed for use in both the hand held unit and the analytical device. The asbestos counting software has been developed and verified against an image generation algorithm which has also been developed within this Work Package.

Work package 5 has been to design a filter, filter housing and latterly a pump unit to force air through a filter. All the work has been undertaken by Luftfilterbau. The filter was to collect particles, fibres and debris from the air on one surface. The filter surface is analysed by laser detection systems developed within this project, ascertaining if asbestos fibres are present, otherwise the sample is regarded as safe.

As the project has progressed the filtering and scanning operations have been separated. Though originally considered as one entity the many problems identified mostly involved contamination issues which would give rise to false readings by the on-board detection systems. The advantages of separating the pump from the laser detectors were therefore as follows:

The pump can be handled in a more robust way because sensitive items have been removed;
The pump unit will be better suited to dust collection via a probe;
Multiple pump units can be left monitoring large spaces or many rooms; one laser unit can read many pumps;
The pump can be set to take readings for fixed / extended periods, continuous monitoring (mains powered);
The pump can remain in a contaminated environment; a shaped bag could seal most of the unit for easy cleaning;

A pump unit was proposed at a brainstorming event held by Partners at TWI, which seems to have solved all of the initial problems. The pump unit was originally constructed from MDF and metal plate. This gives a robust simple solution which could be incinerated if necessary.

The original pump was designed for flow rate of 2.8 l/min which proved to have insufficient power when the filter was in place and was contaminated. A replacement pump rated at 10 l/min was deemed suitable when tested by AMT. The initial pump version used plain filter media trapped between the aluminium window and a sealing material bonded to the MDF.

The filter type selected was MPPS with an efficiency of 90 to 95%. The filter which looks like white paper (slightly thicker) is produced with a textured rough side and a smooth side to be used for particle collection. The filter media size is 30 x 30mm which arises from the scanned area by the laser system which is given as 6000 x 6000 points of five microns diameter give 30mm x 30mm of scan. Glass fibre has been selected as the filter, to withstand the laser power. Traditional filter media like nitrocellulose were not appropriate for this application.

The filter media area is required to be covered by a sticky dielectric tape after use, flattening fibres, preserving the sample and reducing contamination issues. The tape will be manually placed on the filter prototypes.

The Nofer Institute has endeavoured to determine realistic contamination levels from a range of industrial environments. This has allowed representative samples to be generated which have been exchanged to ensure compatibility between Nofer, Applied Materials Technology and Luftfilterbau. This work had a direct impact on sample imaging using in WP4.

The two prototype devices were successfully manufactured in work package 6.. The approach adopted to undertake this work package was consistent with the overall project methodology. This modular design approach was brought to fruition by incorporating the outputs of other work packages as well as the developments within work package 6, in order to realise an assembly for use with functional asbestos testing. The components design and manufactured for final integration where

Component 1: Laser diode.

The laser diode had the role of light source. A high quality laser beam was essential to ensure the necessary diameter spot. The laser diode was manufactured by applying a microlens to a c-mount laser diode chip with sub-micron precision. The lensed diode was appropriately packaged and combined a miniaturized electronic control circuit completing this component. This laser had the required beam characteristics as identified in work package 3.

Component 2: Beam manipulator.

The beam manipulation was undertaken by the optical sled designed, developed and built in work package 3. This sled contained a number of sub-components to provide the necessary beam handling procedures. These were;

A diaphragm and focusing lens to provide spatial filtering and selection of the most intense laser beam mode.

A beam expander, mirrors and collimator to provide the optimum beam diameter for polarization.

A polarization rotator, mirror and XY scanner provided a movable polarized beam.

The final optical subcomponent was a telecentric F-Theta lens which ensured that the beam was always focused and delivered perpendicular to the target surface, thus ensuring that the conditions for refraction and reflection of the beam by the sample are identical over the whole scanned area. Finally a Hamatsu silicon based detector was used to capture the resultant signal.

Component 3:Signal interrogation and analysis.

This was a FPGA integrated circuit processing board. This board had a number of essential characteristics, namely; low power operation, significant processing power, significant on-board memory, expandability and connectivity and compact sized. This was achieved by having a 10 layer PCB.

The FPGA had embedded an advanced optical image simulation software, which enabled a fibre detection and counting system boasting a graphical user interface making it practical and simple to use and possessing three methods of estimation: 1) Manual estimation, 2) Early detection and, 3) Analytical method.

Component 3: Filter and Pump.

Considerable optimisation of these components was undertaken during this work package to provide the functionalities desired by the end users. This included a disc-based filter cartridge design with failsafe system including an RFID tag. The used filter is sealed by using a simple over-under-pressure tool directly after the test but before the holder of the cartridge is opened to release the cartridge. The sealed cartridge is stored in a polycarbonate magazine tray may hold up to 50 cartridges.

The pump was designed to be readily decontaminated, provide failsafe filter exchange and be rugged and watertight. The optimized pump was based on a miniaturized side channel blower allowing an airflow rate of 130 ltr./min which enabling a test time of 10 minutes.

Power supplies and control electronics:

Power supply to the device was via a custom built lithium battery pack. The provided power to the control board, TEC and laser driver board, detector amplifier and analysis processor. Processor and control boards integration was via RS232 ports with a full communications protocol being followed.

The analytical system shared all the above components with the addition of a composite white light laser system which is made up from red green and blue lasers, which through a series of optics are combined to form a single beam which approximates white light in appearance when tuned correctly.

In Work Package 7 bulk samples and samples recovered from airborne particulates were provided from "live" field conditions from the end user partners, these samples were evaluated by NIOM using standard methods, showing a range of asbestos content.

Chrysotile asbestos was encapsulated and used as the demonstrator sample to validate the operation of the hand-held unit.

The operation of the central hand-held unit was refined using a series of software and firmware based modifications. All the necessary integration activities were undertaken, specifically the establishment of a communications protocol between the control board and the processor unit which uses an RS232 protocol to send commands and return responses and results, and an SPI interface to send the image data to the processor unit.

The handheld unit clearly allowed the identification of asbestos via the optical signal resultant from the chrysotile sample compared with the simple reflection based comparisons. The use of the polarizer allows clear discrimination of the optically active (birefringent) material by having considerably different signals in the horizontal and vertical direction.

The optimisation and refinement of the detector was completed as was the verification of its operation. Demonstration of operation was provided to the partners at the final project meeting. Demonstration was shown on real asbestos (encapsulated for health and safety reasons).

The commonality of the approach of the hand-held and analytical prototypes is such that the verification of the detection system for both systems has been shown. The quantification software has been developed and refined (see report deliverable D4), however, the delays in the project due to fundamental difficulties (see report deliverable D3), did not permit the final quantification trials to be undertaken

The timescale of the development programme did not allow for field trials for the prototype to be carried out on either system.

In summary, the main problem encountered in the project was the technical challenge in producing an accurate, reproducible diode laser with the required beam characteristics. The scale of this challenge was not fully appreciated during the preparation of the project. The full scale of the challenge only became clear during the second reporting period of the project. The need to both maximise the laser energy transmitted through to the filter being analysed whilst requiring a extremely uniform beam demanded an extremely complex secondary optic system.

The only method that would allow the complete range of laser characteristics to be achieved, was the use of a 100 micron diameter cylindrical lens. This needed to be located relative to the laser diode to sub-micron levels of accuracy.

The project partners did not initially have the capability to undertake manipulation to this level of precision. The purchase of a facility that could achieve this was beyond the scope of the project in terms of cost (estimated cost in excess of 150k EUROS) and delivery timescale given that it would be a bespoke piece of equipment.

The skills and, fortunately, some of the necessary equipment existed within the partnership to build this equipment. Therefore, a very high precision micro-manipulator capable of six axis linear and rotational control to sub-micron levels was designed, built and proven within the project.

This activity was both time and effort consuming, which was represented in the need for a project extension and the overspend by the partners involved.

The delay in the availability of the prototypes prevented the field trials being undertaken, however, demonstration of the capability of the hand held unit to detect asbestos was very well received by all partners at the final project meeting.

The project was a very significant technical challenge, the development of a diode laser with a very high unifrom quality. The scale of the challenge was far greater than that envisaged at the inception of the project. The precise identification of the fundamental issue to be solved occurred at a relatively late stage in the project. It is unlikley that this could have occurred any earlier as a series of interlinked activities need to be completed before the hurdle became apparent.

The partnership responded to this challenge by directly addressing it by building a micro-lenser with sub-micron resolution. This required a considerable level of effort above that identified in the technical annex. The driver to do this was that without such a positioner a laser with the necessary characteristics could not be made and the prototype would not be able to achieve its goal of detecting asbestos fibres.

The consequences of this additional activity is that the project faced a considerable delay compaired to the planned timescale. Even with an approved extension of five months the testing activity demonstrated the capability of the system but did not undertaken the envisaged field trials.

This was addressed at the final project meeting. The SME end-user partners were clear in their support of the project and the developments undertaken. The lack of field trials was accepted as a necessary price to pay for the considerable achievements made. Whilst some field trials would clearly have been desirable, it was recognised that a full testing programme involving the national regulatory bodies would be required to gain the necessary approval for the devices to be ready to be made commercially available. Such a programme was recognised as being considerably beyond the scope of this project.

At the final project meeting, the SME beneficiaries of the project were very clear in their wish to continue the development of the devices. This wish was driven both by the continued lack of a alternative to the traditional laboratory methods, and by the progress achieved by the consortium in the project.

It can be concluded that a hand-held asbestos detection system to provide early warning of the presence of asbestos particulates in the atmosphere has been developed. The optical properties of asbestos fibres were utilised to provide an early warning of their presence. A novel concentration system draws the air through a removable cartridge containing the particulates in a way that also provides an exposure record. This device was initially aimed at having a weight less than 1.0kg however this was not achieved, since some of the key components necessary were almost this weight on their own. The detection of fibres in the presence of other airborne particles was not demonstrated, but is considered highly likely. The hand held device is powered by a rechargeable battery as specified although this has an operating capability of approximately 5 hours rather than the target of at least 8 hours. At present the warning system is via a visual display only. Milestone one was achieved on the target, the second and third milestones were behind target but were achieved.

A portable automated analytical system capable of identifying, counting and measuring asbestos particulates was developed It used the same techniques as the hand-held system but had the potential capablity of determining the type and amount accurately of the specified particulates in a given airspace, or from a personalised cartridge from the hand-held system. It possessed automatic image recognition software to measure and count particulates present in a rapid real-time approach, as aimed for. This system was targeted to weigh less than 50kg, this was achieved with a prototype weight of 20kg. The detection of fibres in the presence of other airborne particles was not demonstrated, but is considered highly likely. This equipment was powered by the mains electricity supply. Milestone one was achieved on the target, the second and third milestones were behind target but were achieved.

A filter system capable of collection and storage of particulate samples containing asbestos was developed. The filter system was integral to both the hand-held and portable devices. A long term storage capability was proposed in detail. The system utilised replaceable filters and could operate for about five hours without requiring change. The initial manufacturing specification (Milestone 1) was available on time.

The software capable of identifying and automatically counting asbestos fibres was developed on time. (Milestone 2).

Robust and compact packaging solutions for the asbestos detection systems were developed. The cost of this solution was not finalised. Prototype units were available but delivery was later that the revised schedule (Milestone 3).
Potential Impact:
The PORPARDET project was aimed at the development and ultimate testing of devices capable of identifying and measuring asbestos fibres. Such a device is not available in the commercial market place, nor are there any devices available as research tools of which the partnership is aware. The challenges facing the partnership were therefore threefold:

- The initial technology readiness level of the devices was low
- The demonstration of capability was target to the end of the project
- The development undertaken may have significant exploitation capability and so the release of information into the public domain needed careful control

The partnership believed that significant early dissemination may have had the effect of prematurely stoking market expectations. In combination with this, the significant technical challenges faced by the partners reinforced this precautionary approach. The development pathway necessary to overcome these hurdles was finally highlighted in the final eight months of the project, precluding early dissemination of device design and testing.

However, the modular approach taken in the project, did allow the development of the analysis software. Public dissemination of this information was undertaken to illustrate the benefit of Framework 7 sponsored project. The demonstration of this software capability was seen as a positive method of raising the profile of the project without compromising the product development or raising unrealistic expectations. The paper presented in public fora is given in section 4. The meetings at which this presentation was disseminated were:

FP7 for the benefit of SME organized by Cyprus Research Promotion Foundation - 14 October 2009 - Presentation given by Dr. Tasos Kounoudes, Chief Executive Officer, SignalGeneriX Ltd

Beyond the project close, Lateral Logic is planning a presentation at the British Occupational Hygiene conference in Buxton. This was originally to have taken place in April but the event has been rescheduled as part of the BOHS Autumn Scientific meeting which will run on the 14/15th November in Leeds with the following abstract:


Development of a Portable Asbestos Detection System

This presentation will outline the development of a portable airborne asbestos detector which has been produced as a result of the two year PORPARDET project which is nearing completion. This activity is a collaborative EU project which is funded under the FP7 Action for SMEs, and lead by TWI. The project aims will be outlined and the progress towards a working unit and initial trial results will be presented.

The original project DOW (10 September 2008) did not specify a project web-site. Following discussion with the REA it was agreed by the project partners at the 12 month meeting that a website should be set up. This web-site (see online) was set up by partner Signal Generix using content provided by all partners.

Two videos were generated within the project. The first video was to demonstrate the proof-of-principle for the approach using an optical bench arrangement. This video was shown to all partners at the 12 month partner meeting and provided to the EC with the first periodic report. The video was also made available via the website.

A second video was generated at the end of the project illustrating the project achievements. This was made available via the project web-site.

As well as the above dissemination activities, the partnership also engaged in networking activities, these included attendance at the 8th International Conference "Health, Work and Social Responsibility. The occupational hygiene's and the integration of environmental health and safety". Attendance was by project partner Professor Irena Szadkowska-Stanczyk who presented papers on the topics:

Pulmonary function changes in construction industry workers exposed to silica dust;
Biocontanimust in intensive animal production and its toxic affect on workers respiratory system.

These papers were not specifically related to the PORPARDET project, but the theme of airborne sources of contamination is central to the aims of the project. Professor Szadkowska-Stanczyk's leading expertise in this area is demonstrated by her role in this conference.

With regards to the potential impact of the project.
Asbestos has potentially more than 3,000 uses and the current asbestos problem is worldwide. It is estimated that 10 million asbestos related deaths occur each year, and that number is rising. This project has the benefit of partners, from 7 different EU countries showing their concern to protect their workers and the environment. It is an urgent and ongoing problem and they are hastening to control and reduce the enormous risk to their workers.

Experts have called for continuous monitoring for those working or living in previous contaminated areas. In an ideal world, workers should assume they are working with asbestos, unless they know for certain they are not. However, Trade Unions know that in practice, workers do not assume they are working with asbestos and do not take precautions (UK Trades' Union Congress 2005).

This provides the context for a rapid accurate testing procedure for asbestos, which can be used at any site. The main issue faced by workers is the need for quick, effective detection of asbestos fibres in the atmosphere. Currently, the level of asbestos fibres suspended in the air is determined by counting the fibres captured on a filter paper. The test procedure requires a skilled operator with a specialist microscope. Analysis can take several hours, be subject to human error and is often performed away from the actual test site. The time lost waiting for the test results is a major expense to demolition or decommissioning contractors.

This project targeted the development of two related asbestos detection systems integrated into a portable device, which can either be hand-held or placed within a working environment. Prototype devices have been produced.

The requirement for a device that measures asbestos fibres in the air will be needed for many years to come, as some countries are still mining, exporting and importing asbestos, and then dismantling. The international trade in asbestos will by default also provide a global market for a reliable and rugged detection device.

The lower asbestos test and compliance costs that are potential outputs of this project should increase the competitiveness of European companies, enabling them to access new markets for safe asbestos disposal. This will create more jobs as well as having the additional advantage of encouraging companies to dispose of asbestos waste in a safe and environmentally manner, rather than dumping the waste in a third-world country.

One of the main cost benefits for Europe will be the potential savings in health care, insurance and litigation costs associated with diseases from asbestos exposure, increased sales of equipment and ultimately more jobs. The capture of data can be used for historical purposes that will assist workers gain compensation from negligent employers. In 2006, a worker secured a $25 million jury verdict in a trial against a major motor manufacturer for a New York City brake reliner who lost his right lung to mesothelioma. This is believed to be the highest verdict to date. In 1996, four asbestos workers won a $64.65 million award.

About 700 ships are scrapped every year, most of them in Asian ship breaking locations. Most of the ships built in the 60's and 70's contain extensive amounts of asbestos and other toxic substances. There are 150 oil and gas fixed platforms in the North Sea, 60% are older than 20 years and nearing their end of life. Local asbestos detection is critical on these platforms as they are far from the analysis laboratories and do not currently have the equipment on the platforms to monitor asbestos in the air.

A surge in asbestos-related claims over the coming decades could land UK insurers and employers with a bill of up to £20bn. A study (Guardian Unlimited) predicts that as many as 200,000 new insurance claims from UK workers exposed to asbestos are expected over the next 30 years.

Most people who have developed asbestos related illnesses have inhaled extremely fine particles. In particular fire and rescue workers need to know when they are in contact with asbestos particles, so they can take the appropriate precautions. Most workers frequently assume they are not working with such hazardous materials and do not take precautions. Analysis for these particulates is currently a costly and lengthy process. Air samples are taken on site, and are transferred to a laboratory for analysis. The analysis may take days, meanwhile work on the suspected site ceases, thus incurring expense. The cost for regular monitoring on-site is currently high as is the cost of long term health care for workers with contaminated lungs. The lower asbestos test and compliance costs potentially made possible by this project would also increase the competitiveness of European companies, enabling them to access more markets for safe asbestos disposal. This will create more jobs as well as having the additional advantage of encouraging companies to dispose of asbestos waste in a safe and environmentally manner. Because of the lowering of the costs associated with detection of asbestos, there would be less cause to dump the waste disregarding EU regulations.

The filter systems designed for use with the detectors will also generate an ongoing market for these consumables. The detection devices will find a ready market worldwide which will continue to grow as developing countries tackle asbestos exposure issues.

The new improved method devices will lead to improved or simplified risk management procedures at the workplace. Litigation against employers from workers falling ill from asbestos related illness, is long term and costly. Long-term care is often a necessity, and compensation from a neglectful employer would assist with medical care and support families need. The filter storage system would keep a record of the analysis taken at a particular site. This information would assist the worker to prove that asbestos was present at that site and at what levels.

The impact on the end user project partners in the longer term will be to assist them to continue to comply with the EU Directives on asbestos by assisting them in identifying levels of danger. The devices have the potential to allow small companies to rapidly respond to the threat posed by asbestos and to protect their workers.

The project draws on the skills of companies and research institutes from across Europe. The project supported the European employment strategies confirmed in the Barcelona Council of 2002, as it has the potential to create new job opportunities, not only through the development of new products, but also by decreasing the compliance costs associated with asbestos and so making European companies more competitive.

Asbestos is a Europe-wide problem and needs to be tackled at a European level. The practices adopted for handling asbestos vary between each member state, but are becoming standardised through current EU directives. The products resulting from this project will help the implementation of the new directives and assist small companies to adhere to the Directives by reducing their costs.

The project, with the assistance of the seven European partner countries was involved in considerable information exchange information, technologies development and relationship building. There is a firm commitment from the partners to continue this relationship beyond the end of the project

The project has provided an opportunity for the SMEs to establish a trans-national and complementary co-operation among themselves and the European RTD performers, guarantying an effective approach to the problem of asbestos and therefore having a greater impact than would have been seen with National projects.

The SME partners AM Trans Progres and Dehaco are both involved with demolition activities involving testing for asbestos. Their current technologies have been challenged by the innovative technology described in this proposal and will provide them with improved and valuable new products to carry out their work.

Through the partnership established in this project, 4 European companies have had the opportunity to work together and establish a close relationship with large companies such as DNV, with its long interest in assessing the risks associated with asbestos. The complementary expertise of the proposers, their geographical distribution, and the critical mass in human and financial resources, gives the European added value to the consortium necessary to achieve the project objectives.

The launching of competitive devices was the only forseeable negative factor that could affect the impacts mentioned above. The partnership is not aware of any such device nor the development of such a device. On this basis, and considering that It is extremely unlikely that prhibition on the use of asbestos will be reversed, the large amount of material in existing structures will always need controlled handling at disposal and safety first with rescue personnel in emergency situations will always be a priority. These issues are likely to create a long lasting market for the devices and their consumables.

The project has enabled the early stage prototype devices to be made that could have significant potential to reduce the risks of accidental exposure to a known hazard that is in widespread existence. The devices allow the rapid determination of the presence of asbestos.
The development of these devices has been brought about by a number of key achievements by the project partners. These include:

- The design of novel electronic circuitry.
- The design and building of a unique micro-lensing facility.
- The development of an advanced processing circuit.
- The creation of unique software algorithms allowing fibres to be counted.
- Revolutionary optical design.
- High performance pump and filter assembly.

The capability of recognising asbestos gives the hand-held unit a unique capability which can be used as the platform for the development of products specifically designed for the end-user in the construction/demolition industry.

The precise methods of exploiting these results has not yet been defined. As identified above considerable know-how has been developed. This includes hardware capability, assembly methods, software and novel designs. Further testing, validation and compliance against standards and ultimately acceptance by the various national standards authorities will provide the springboard to commercialisation. These activities were outside the scope of the project and therefore the partnership is now in active discussion of how to progress the development from its current state to one that will allow the launch of commercial devices that can be immediately adopted by the industrial end users.

The potential impact of the project is significant in a number of areas.

From a strategic perspective there currently are no rapid, accurate methods for determining whether asbestos is present in an industrial environment. Traditional testing is expensive and slow, in practice this can lead to exposure risks being taken. Health insurance and litigation costs across Europe are scheduled to increase to reflect the human suffering brought about by exposure to asbestos. The devices developed in this project may provide an opportunity to bring about a more rapid and effective decrease to all these issues than legislative measures.

Within the ship and offshore industry, decommissioning and breaking of vessels as well as repair of ships and offshore structures can be reduced in cost by undertaking this activity in Asian shipyards. The development of a viable and rapid detection method in the EU, provides those companies undertaking this activity with a technical advantage that can be transformed into reduced cost without increased risk. This will provide European companies with a competitive commercial edge over their Asian counterparts.

The SME partners, led by Lateral Logic, recognise the progress made by the project and the central role that the support of the EU via the Research Executive Agency has had in the achievements made. A significant number of potential impacts from the project have already been identified, these include:

- The development of skills within their existing workforces;
- The establishment of new networks across Europe;
- The creation of new and unique enabling technologies;
- The production of novel prototypes that can be used as the platform for new products;
- The formation of an innovative new sensing technology that may form the basis for future environmental monitoring methods.

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