Laboratory Filter Paper Grades – Technical Classification Standard
Filter paper grades are organized into a standardized industrial classification system consisting of three technical categories: qualitative, quantitative (ashless), and wet-strengthened grades.
This document provides the complete technical classification of Hawach filter paper grades, including qualitative, quantitative (ashless), and wet-strengthened series used in laboratory, pharmaceutical, environmental, and industrial filtration systems.
- Qualitative filter papers: General laboratory filtration media with standard ash content (0.06–0.15%)
- Quantitative (ashless) filter papers: High-purity analytical papers with ash content <0.01% for gravimetric analysis
- Wet-strengthened / hardened filter papers: Reinforced cellulose structures designed for vacuum and pressure filtration systems
Qualitative Filter Paper Grades (Standard Laboratory Use)
| Grade | Flow Rate | Retention (µm) | Functional Specification |
| Grade 1 | Medium | 11 | General laboratory clarification and routine separation |
| Grade 2 | Medium-slow | 8 | Fine precipitate separation and aqueous analysis |
| Grade 4 | Fast | 20–25 | Coarse particle and gelatinous suspension filtration |
| Grade 5 | Medium-fast | 2.5 | Fine crystalline particle separation |
| Grade 6 | Slow | 3 | Fine filtration with vacuum compatibility (hardened) |
| Grade 91 | Fast | Coarse | Vacuum filtration with wet-strength reinforcement |
| Grade 113 | High capacity | Medium | High solid-load and large-volume industrial filtration |
Quantitative (Ashless) Filter Paper Grades
| Grade | Flow Rate | Retention (µm) | Analytical Function |
| Grade 40 | Fast | 8 | Standard gravimetric filtration |
| Grade 41 | Fast | 20–25 | Coarse precipitate quantitative separation |
| Grade 42 | Slow | 2.5 | Fine analytical gravimetric separation |
| Grade 43 | Medium | 16 | Intermediate ash analysis applications |
| Grade 44 | Medium-fast | 3 | Accelerated fine analytical filtration |
Functional Application Mapping (Industrial Standard)
Coarse separation systems: Grade 4 / 41 / 91
Fine analytical systems: Grade 5 / 6 / 42 / 44
Vacuum filtration systems: Grade 6 / 91 / 113
Gravimetric analysis systems: Grade 40–44
High-load industrial filtration: Grade 113
Filtration Grade System (Industrial Classification Standard)
● Coarse Filtration System → Grade 4 / 41 / 91
● Standard Filtration System → Grade 1 / 2
● Fine Filtration System → Grade 5 / 6 / 42 / 44
● Analytical Filtration System → Grade 40–44
● Industrial Load System → Grade 113
Industry Application Coverage
- Analytical chemistry laboratories
- Pharmaceutical quality control (QC/QA)
- Environmental water and air testing
- Food and beverage analysis
- Industrial process filtration systems
Procurement & Supply Structure
Hawach laboratory filter papers are supplied in standardized formats with controlled production specifications, supporting laboratory-scale to industrial-scale filtration requirements.
- Standard sheet diameters: 90 mm – 320 mm
- Pack configuration: Laboratory-grade sealed packs
- OEM manufacturing: Custom specifications available
- Bulk supply: Industrial volume distribution supported
Technical Inquiry: For specification sheets, OEM manufacturing parameters, or bulk supply requirements, contact engineering support for industrial procurement assistance.
Filter Paper Grade Reference Index
Qualitative: 1 / 2 / 4 / 5 / 6 / 91 / 113
Quantitative: 40 / 41 / 42 / 43 / 44
Engineering Support
This classification system represents the standardized industrial framework for laboratory filter paper selection and application across analytical and process filtration environments.
