TECHNICAL SUPPORT

Yiran® Technical Support

Comprehensive product selection guides, international standards interpretation, installation & maintenance guidelines, and technical document downloads — helping customers efficiently and correctly select and maintain Yiran® filtration products.

Selection Guide

Filtration Efficiency Grade Cross-Reference

Understand the correspondence of efficiency grades across different standard systems to accurately select the required filtration efficiency

Yiran® Classification Brand Series EN 779
(Legacy)		 ISO 16890
(Current)		 ASHRAE 52.2 GB/T 14295 EN 1822 Target Particles Typical Application
Pre-Filter BasicClean G2 ISO Coarse 40–50% MERV 4 YX-C1 — ≥10μm coarse particles 1st stage pre-filter, intake protection
Pre-Filter BasicClean G3 ISO Coarse 55–65% MERV 5 YX-C2 — ≥10μm coarse particles Panel / Paint-Stop
Pre-Filter BasicClean G4 ISO Coarse 70–80% MERV 7–8 YX-C3 — ≥5μm particles AHU fresh air pre-filter
Medium eFlow / DuraVault M5 ISO ePM10 > 50% MERV 9–10 YX-Z1 — 3–10μm particles Comfort HVAC pre-filter
Medium eFlow / NanoShield M6 ISO ePM10 > 70% MERV 11–12 YX-Z2 — 1–3μm particles Precision process pre-filter
Semi-HEPA V-Compact / W-Max F7 ISO ePM1 > 50% MERV 13 YX-G1 — 0.5–1μm particles HEPA pre-stage protection
Semi-HEPA V-Compact / W-Max F8 ISO ePM1 > 70% MERV 14 YX-G2 — 0.4–0.5μm particles Cleanroom pre-stage
Semi-HEPA BoxCel / MegaBox F9 ISO ePM1 > 80% MERV 15 YX-G3 — 0.3–0.4μm particles Strict control pre-stage
HEPA eFlow / DuraVault — — MERV 16 — E10 ≥0.3μm · ≥85% ISO Class 8 Cleanroom
HEPA eFlow / NanoShield — — — YG-C H13 ≥0.3μm · ≥99.95% ISO Class 5 Cleanroom
HEPA DuraVault / NanoShield — — — YG-B H14 ≥0.3μm · ≥99.995% ISO Class 5 · Stringent
ULPA UltraPure — — — — U15 ≥0.12μm · ≥99.9995% Semiconductor ISO 1–4
ULPA UltraPure — — — — U16–U17 ≥0.12μm · ≥99.99995% Ultra-Pure · Wafer Fab
Standards Framework

International Air Filtration Standards Reference

Yiran® product design, testing, and performance evaluation follow these international and Chinese standard systems

ISO 16890

International Standard for General Ventilation Filters

The new international standard replacing EN 779. Classifies by ePM1, ePM2.5, ePM10 efficiency, and ISO Coarse for coarse filters. Leading international brands have fully adopted this standard for product labeling since 2024.

EN 1822

European Standard for High-Efficiency Air Filters

The benchmark standard for HEPA/ULPA filters. Specifies scan-by-scan (MPPS) testing for filter efficiency and leakage, with grades E10–U17.

ASHRAE 52.2

US Filtration Efficiency Standard

Uses the MERV rating system (1–16), with weighted efficiency scoring across three particle size ranges between 0.3–10μm. Widely used in North American and Asia-Pacific HVAC markets.

EN 779

Legacy European Standard for General Ventilation Filters

Classifies general ventilation filters as G1–G4 (coarse), M5–M6 (medium), F7–F9 (fine). Superseded by ISO 16890 but still referenced in many project specifications.

GB/T 14295

Chinese National Standard for Air Filters

Chinese national standard specifying efficiency classifications: Coarse C1–C4, Medium Z1–Z3, High-Medium G1–G4, and Semi-HEPA YG-C/YG-B for HVAC filters.

ISO 14644

International Standard for Cleanrooms and Controlled Environments

Cleanroom air cleanliness classification (ISO 1–9) based on particle concentration. Yiran® HEPA/ULPA solutions support customer cleanroom operations per this standard.

ISO 29461

Gas Turbine Intake Air Filter Test Standard

Specifically addresses performance testing of gas turbine intake air filters, accounting for water separation, pulse cleaning, and dust-loaded operation conditions.

VDI 6022

HVAC System Hygiene Standard

Published by the Association of German Engineers (VDI), specifies hygiene requirements for filter installation and maintenance, widely referenced in European HVAC projects.

EU GMP Annex 1

Pharmaceutical GMP Annex 1 – Sterile Products

EU GMP requirements for air cleanliness grades, filtration system validation, and monitoring in sterile pharmaceutical production environments. Core reference document for Yiran® pharmaceutical filtration solutions.

Installation & Maintenance

Installation Guidelines & Precautions

Proper installation is the cornerstone of efficient filtration system operation — the following are general installation specifications for all Yiran® filter types

Panel & Bag Filter Installation

  • Before installation, check that the frame sealing surface is flat and the gasket is free of damage or aging
  • Airflow direction must match the arrow marked on the filter
  • When installing bag filters, ensure the bags are fully expanded without folding or compression
  • Apply uniform force on fastening devices to avoid localized over-tightening causing frame deformation
  • For side-access installations, ensure slide rails move smoothly without obstruction
  • After installation, verify no visible light leakage between filter and frame

HEPA/ULPA Filter Installation

  • Perform a visual inspection before installation to confirm no shipping damage
  • Wear clean gloves to prevent skin oil contamination on the filter downstream face
  • For fluid-seal installations, ensure complete gel sealant filling
  • For dry-seal installations, tighten bolts evenly to torque specifications
  • After installation, DOP/PAO in-situ leak testing must be performed
  • Record each filter's model, serial number, and installation position

High-Temperature Filter Installation

  • Use high-temperature resistant gaskets (e.g., PTFE or ceramic fiber gaskets)
  • Select fasteners of high-temperature material to prevent loosening from thermal expansion
  • Apply gradual temperature ramp-up during system heating to avoid thermal shock
  • After initial use, re-tighten after stabilization at rated temperature
  • Periodically check sealing surfaces for thermal deformation or leakage
  • When replacing, wait until the system cools to a safe temperature before handling

General Maintenance & Replacement

  • Use differential pressure gauge readings as the primary replacement criterion, not elapsed time
  • For primary/medium-efficiency filters, replace when pressure drop reaches 2–2.5× the initial resistance
  • For HEPA filters, decide replacement timing based on on-site leak test results
  • During replacement, simultaneously inspect and clean the frame sealing surfaces
  • For chemical/molecular filters, determine replacement based on breakthrough saturation
  • Record replacements in the O&M log for LCC trend analysis

Dust Cartridge & Collector Installation

  • Before cartridge installation, check the cleanliness and roundness of tube-sheet holes
  • Install venturi and cartridge in alignment — no offset
  • Apply uniform preload force on the cartridge bottom clamping device
  • Align pulse-jet nozzle center with venturi center
  • Before first collector startup, check duct sealing and valve operation
  • Adjust cleaning pressure and cycle per ANSI or national standards

Transportation & Storage Precautions

  • Filters should be transported in original packaging to avoid compression and impact
  • HEPA/ULPA filter packaging must not be opened until just before installation
  • Storage environment should be dry (RH < 80%) and avoid high temperatures (< 50°C)
  • Paper-frame filters should be protected from moisture and mold; avoid long-term storage
  • Chemical filters must be stored in sealed packaging to prevent premature adsorption failure
  • Follow FIFO (First In, First Out) principle for inventory rotation
FAQ

Frequently Asked Questions

Q: How do I choose the right filter combination for my AHU?
A: Generally recommended as a three-stage or multi-stage combination: G4 (pre-filter, capturing ≥10μm particles) + F7 (medium-efficiency, capturing 0.5–1μm particles) + final stage selected per requirements (F7 is sufficient for comfort HVAC; cleanrooms require H13 or above). Specific parameters (airflow, dimensions, resistance) should be determined based on actual AHU operating conditions. Yiran®'s AI selection tool can automatically recommend the optimal combination for you.
Q: What is the difference between ISO 16890 and EN 779? Which standard should I reference?
A: EN 779 uses letter+number grades (G/M/F), while ISO 16890 classifies by measured ePM1/ePM2.5/ePM10 efficiency (more reflective of actual PM concentration reduction capability in service). ISO 16890 is the current international standard; EN 779 has been withdrawn but still appears in many project specifications. Yiran® products are dual-labeled with both efficiency ratings to ensure accurate adaptation to both new and legacy projects.
Q: When should a HEPA filter be replaced?
A: HEPA filter replacement is not determined by fixed time intervals but by: (1) in-situ leak test failure (leak rate exceeds allowable limit); (2) resistance increase to 2–2.5× the initial resistance, causing insufficient system airflow; (3) visible damage or media failure. It is recommended to perform periodic (every 6–12 months) on-site leak testing.
Q: What is the maximum temperature that high-temperature filters can withstand?
A: Yiran® high-temperature filters have three grades: MT Series (120°C, suitable for medium-temperature painting oven sections), HT Series (250°C, suitable for topcoat and clearcoat ovens), and UHT Series (above 350°C, suitable for special high-temperature processes). When selecting, pay attention to the temperature compatibility of the gasket material.
Q: How should I choose between G2, G3, and G4 pre-filters?
A: G2 is suitable for particularly coarse dust environments (e.g., mining, metallurgy fresh air); G3 is suitable for general industrial fresh air; G4 is suitable for comfort HVAC and as a pre-stage for medium-efficiency filters. Selection principle: while achieving the required coarse particle interception, use the lowest possible resistance grade to reduce fan energy consumption.
Q: How is the service life of chemical/molecular filters determined?
A: Chemical filters remove gaseous pollutants through adsorption/chemical reaction; their lifespan depends on: (1) inlet pollutant concentration and composition; (2) saturation capacity of the activated carbon or impregnated media; (3) target outlet concentration limit. Yiran® provides periodic breakthrough testing services to help customers accurately determine replacement timing.
Q: Can Yiran® products replace filters from leading international brands?
A: Yes. Yiran® products are designed to benchmark against leading international brand standards, with key performance parameters (efficiency, resistance, dust-holding capacity) reaching equivalent levels. Product outline dimensions and mounting interfaces are designed to common industry standards for direct replacement. It is recommended to confirm HVAC/filtration system compatibility before substitution.
Q: How can I obtain Yiran® product test reports and certification documents?
A: Please contact the Yiran® Technical Support team for the latest product test reports, CE/UKCA declarations of conformity, and ISO 9001 certification documents. You may also download product catalogs and general technical manuals from the Download Center below. For batch-specific factory test reports, provide the product serial number to retrieve them.
Download Center

Technical Document Downloads

Product catalogs, technical manuals, test reports, and installation guides provide comprehensive references for your selection and maintenance

Cat.

Yiran® Product Master Catalog

Complete overview of 13 product lines

PDF · ~24 MB
Tech

Technical Selection Manual

Specs, performance curves, selection guide

PDF · ~18 MB
Test

Product Test Reports

ISO 16890 / EN 1822 efficiency tests

PDF · ~8 MB
Inst.

Installation & Maintenance Guide

Installation specs for all filter types

PDF · ~6 MB
Cert.

System Certification Documents

ISO 9001/14001 compliance statements

PDF · ~4 MB
BIM

3D / BIM Model Library

Product models in RFA/DWG format

ZIP · ~35 MB
MSDS

Material Safety Data Sheets

MSDS/SDS safety information

PDF · ~3 MB
WP

Industry White Papers

In-depth air filtration technology articles

PDF · ~10 MB

For additional technical documentation or custom requests, please contact the Yiran® Technical Support team.

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