🔬 PD 6699 (a UK “Published Document” series) is a set of good practice guides for nanotechnologies prepared by BSI Technical Committee NTI/1 (Nanotechnologies), commissioned by the UK Department for Innovation, Universities and Skills (DIUS) to provide guidance for manufacturers and users of nanomaterials. The series consists of three parts: specifying nanomaterials, safe handling and disposal, and assessing airborne exposure in occupational settings — covering the whole process from procurement and use through disposal and occupational health monitoring.
💡 PD 6699 is positioned as a “good practice guide” rather than a specification: it uses recommendations (“should”), explicitly reminds users that “it should not be quoted as if it were a specification”, and cautions that compliance claims must not be misleading. Use the applicable legislation when working.
1. Series Structure 📌
| Part | Title | Subject |
| PD 6699-1:2007 | Part 1: Good practice guide for specifying manufactured nanomaterials | Nanomaterial specification, characterisation, and measurement |
| PD 6699-2:2007 | Part 2: Guide to safe handling and disposal of manufactured nanomaterials | Risk assessment, exposure control, health surveillance, and disposal |
| PD 6699-3:2010 | Part 3: Guide to assessing airborne exposure in occupational settings relevant to nanomaterials | Airborne exposure assessment, instruments, and monitoring strategy |
2. Specifying Manufactured Nanomaterials (PD 6699-1) 📐
PD 6699-1 addresses the experience that agreed specifications between suppliers and users have sometimes failed to ensure batch-to-batch consistency in response to downstream processing and performance. Key points:
- Classification by number of dimensions at the nanoscale (all three dimensions — nanopowders; two dimensions — carbon nanotubes/nanofibres/nanorods; one dimension — nanoscale thin films or coatings);
- Characteristics important for specification (particle size distribution, specific surface area, purity, morphology, surface chemistry, etc.);
- Recommended measurement methods for batch quality control and audit checks (Table 1 and Table 2);
- Impact of contamination on properties and performance and its mitigation, plus packaging, labelling, and transport requirements.
⚠️ Nanomaterial “consistency” depends on characterisation and measurement. If a specification merely says “nanopowder” without defining particle size distribution, specific surface area, and purity, batch-to-batch performance can fluctuate widely and downstream processing becomes unrepeatable.
3. Safe Handling and Disposal (PD 6699-2) 🧪
PD 6699-2 provides guidance for safe handling and disposal of manufactured nanomaterials. Key points:
- Identifying nanomaterial types and characteristics, nanoparticle exposure, and risk;
- Overall approach to managing risks, competence of the risk assessor, and information collection;
- Hierarchy of control and control approaches for various generic tasks;
- Health surveillance, measurement of control effectiveness, spillages and accidental releases, disposal procedures, and prevention of fire and explosion.
🚨 The health risks of nanoparticles are not yet fully understood. Whether hazards are known or unknown, follow a precautionary hierarchy of control — from substitution at source, containment, and isolation to personal protection — and always consider spill disposal and fire/explosion prevention; do not rely on ventilation alone.
4. Occupational Airborne Exposure Assessment (PD 6699-3) 🌬️
PD 6699-3 provides guidance for assessing airborne exposure in occupational settings relevant to nanomaterials. Key points:
- General principles of exposure assessment (the hazard-exposure-risk paradigm, respiratory deposition models, health-related sampling conventions);
- Measurement in occupational settings relevant to nanotechnologies;
- Strategy for exposure assessment (exposure scenarios and possible aerosol release, assessment process);
- Instruments and techniques available for monitoring exposure (including instrument selection based on PD ISO/TR 27628, Annex A).
5. Engineering Practice Essentials 🛠️
- 🔍 Specification first: before purchasing nanomaterials, define key characteristics and measurement methods per PD 6699-1 and write them into the specification to ensure batch consistency.
- 🔧 Source control: apply the hierarchy of control, preferring low-hazard substitution, containment, and isolation to reduce worker contact.
- 📊 Exposure monitoring: select appropriate instruments per PD 6699-3 (particle sizing, aerosol photometers, samplers, etc.) and establish an exposure assessment strategy.
- 📋 Emergency and disposal: prepare spill disposal and waste procedures, assess fire/explosion risk, and implement health surveillance.
6. Frequently Asked Questions ❓
❓ Q: Is PD 6699 mandatory?
A: No. It is a good practice guide that explicitly should not be quoted as a specification, and compliance claims must not be misleading; comply with applicable legislation and product specifications.
❓ Q: What characteristics should a nanomaterial specification include?
A: It should cover key characteristics affecting downstream processing and performance — particle size/distribution, specific surface area, purity, morphology, surface chemistry — and specify measurement methods.
❓ Q: How is nanoparticle exposure controlled?
A: Follow the hierarchy of control, preferring substitution at source and engineering containment/isolation, supplemented by ventilation, personal protection, health surveillance, and exposure monitoring, and consider spill disposal and fire/explosion prevention.
🔍 Q: How should instruments be selected for occupational exposure assessment?
A: Select methods and instruments from the tables in PD 6699-3 Annex A based on particle type (discrete spherical, HARN, agglomerates, etc.) and assessment purpose, considering respiratory deposition and sampling conventions.