ZH
RU
ES

foreign air purifiers

foreign air purifiers, Total:151 items.

In the international standard classification, foreign air purifiers involves: Installations in buildings, Air quality, Rotating machinery, Nuclear energy engineering, Products of the chemical industry, Domestic electrical appliances in general, Floor treatment appliances, Ventilators. Fans. Air-conditioners, Characteristics and design of machines, apparatus, equipment, Domestic safety, Protective equipment, Semi-manufactures of timber, Domestic, commercial and industrial heating appliances, Accident and disaster control, Internal combustion engines, Ceramics, Environmental testing.

Group Standards of the People's Republic of China, foreign air purifiers

T/CPQS E00031.2-2022 International health station—Smart appliances—Air purifier
T/GIEHA 009-2018 Test method for allergen removal performance of air purifiers
T/QGCML 898-2023 Electrode generator for plasma air purification and disinfection machine
T/CAS 542-2021 Technical requirements and evaluation methods of air cleaner removing performance for small particles pollutant
T/CAQI 181-2021 Technical requirements and test methods for vehicle-mounted air purifiers with disinfection function
T/IGIA 002-2021 Evaluation methods and technical requirements of effect for air cleaner under site environment
T/CAB 0104-2021 Artificial atmosphere comfort products Part 7: Air conditioners with fresh air purification function
T/CAB 0104-2022 Artificial atmosphere comfort products Part 7: Air conditioners with fresh air purification function

American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), foreign air purifiers

ASHRAE EQUIP IP CH 28-2008 AIR CLEANERS FOR PARTICULATE CONTAMINANTS
ASHRAE SYSTEMS AND EQUIP IP CH 29-2012 AIR CLEANERS FOR PARTICULATE CONTAMINANTS
ASHRAE QC-06-038-2006 Laboratory Testing of Full-Scale In-Duct Gas Air Cleaners
ASHRAE OR-05-17-2-2005 Performance of Air Cleaners for Removing Multiple Volatile Orgenic Compounds in Indoor Air
ASHRAE CH 24-2000 Air Cleaners for Particulate Contaminants(ASHRAE Handbook: HVAC Systems and Equipment, SI Edition)
ASHRAE CH 24 SI-2000 Air Cleaners for Particulate Contaminants(ASHRAE Handbook: HVAC Systems and Equipment, SI Edition)

ESD - ESD ASSOCIATION, foreign air purifiers

ADV3.2-1995 Selection and Acceptance of Air Ionizers

ASHRAE - American Society of Heating@ Refrigerating and Air-Conditioning Engineers@ Inc., foreign air purifiers

ASHRAE HVAC APPLICATIONS IP CH 46-2015 AIR CLEANERS FOR GASEOUS CONTAMINANTS
ASHRAE HVAC APPLICATIONS SI CH 46-2015 AIR CLEANERS FOR GASEOUS CONTAMINANTS
ASHRAE HVAC SYSTEMS AND EQUIPMENT SI CH 28-2008 AIR CLEANERS FOR PARTICULATE CONTAMINANTS
ASHRAE HVAC SYSTEMS AND EQUIPMENT SI CH 24-1996 Air Cleaners for Particulate Contaminants
ASHRAE HVAC SYSTEMS AND EQUIPMENT SI CH 29-2012 AIR CLEANERS FOR PARTICULATE CONTAMINANTS
ASHRAE HVAC SYSTEMS AND EQUIPMENT SI CH 24-2000 Air Cleaners for Particulate Contaminants
ASHRAE HVAC SYSTEMS AND EQUIPMENT IP CH 24-2000 Air Cleaners for Particulate Contaminants
ASHRAE HVAC SYSTEMS AND EQUIPMENT IP CH 24-2004 Air Cleaners for Particulate Contaminants
ASHRAE HVAC SYSTEMS AND EQUIPMENT SI CH 24-2004 Air Cleaners for Particulate Contaminants
ASHRAE HVAC SYSTEMS AND EQUIPMENT IP CH 29-2012 AIR CLEANERS FOR PARTICULATE CONTAMINANTS
ASHRAE HVAC SYSTEMS AND EQUIPMENT IP CH 28-2008 AIR CLEANERS FOR PARTICULATE CONTAMINANTS
ASHRAE 3842-1995 Fractional Aerosol Filtration Efficiency Test Method for Ventilation Air Cleaners
ASHRAE DA-07-030-2007 An Experimental and Modeling Assessment of Room Air Cleaners for Building Protection
ASHRAE 4529-2002 Measurement and Simulation of the IAQ Impact of Particle Air Cleaners in a Single-Zone Building

GM Daewoo, foreign air purifiers

GMKOREA EDS-T-4715-2011

American National Standards Institute （ANSI), foreign air purifiers

ANSI/UL 867-2013 Standard for Safety for Electrostatic Air Cleaners
ANSI/AIHA Z88.7-2010 Color Coding of Air-Purifying Respirator Canisters, Cartridges, and Filters
ANSI/AIHA/ASSE Z88.7-2010 Color Coding of Air-Purifying Respirator Canisters, Cartridges, and Filters

Korean Agency for Technology and Standards (KATS), foreign air purifiers

KS I 4017-2019 Test methods for remanufactured BLDC motor of air purifier
KS B ISO 6584:2005 Cleaning equipment for air and other gases-Classification of dust separators
KS B ISO 6584:2015 Cleaning equipment for air and other gases－Classification of dust separators
KS C IEC 60335-2-65:2013 Household and similar electrical appliances－Safety－Part 2-65：Particular requirements for air-cleaning appliances
KS C IEC 60335-2-65:2007 Household and similar electrical appliances-Safety-Part 2-65:Particular requirements for air-cleaning appliances
KS C IEC 60335-2-65:2017 Household and similar electrical appliances－Safety－Part 2-65：Particular requirements for air-cleaning appliances

Professional Standard - Nuclear Industry, foreign air purifiers

EJ/T 20027-2012 Verification of purification coefficient of high efficiency particulate air filter in nuclear air treatment systems.Uranin aerosol method
EJ/T 1183-2005 Verification of scrubbing coefficient of iodine adsorbers in nuclear air treatment systems By radioactive methyl iodide

KR-KS, foreign air purifiers

KS B ISO 6584-2015 Cleaning equipment for air and other gases－Classification of dust separators
KS C IEC 60335-2-65-2017 Household and similar electrical appliances－Safety－Part 2-65：Particular requirements for air-cleaning appliances

YU-JUS, foreign air purifiers

JUS B.Z1.300-1990 Cleaning equipment for air and other gases. Clasification of ?ust separators

International Organization for Standardization (ISO), foreign air purifiers

ISO 6584:1981 Cleaning equipment for air and other gases; Classification of dust separators
ISO/FDIS 16000-44:2011 Indoor air — Part 44: Test method for measuring perceived indoor air quality for use in testing the performance of gas phase air cleaners
ISO/DIS 16000-44 Indoor air — Part 44: Test method for measuring perceived indoor air quality for use in testing the performance of gas phase air cleaners
ISO/DIS 16000-43:2023 Indoor air — Part 43: Standard method for assessing the reduction rate of culturable airborne fungi by air purifiers using a test chamber
ISO 16000-36:2018 Indoor air - Part 36: Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber
ISO/CD 16000-43 Indoor air — Part 43: Standard method for assessing the reduction rate of culturable airborne fungi by air purifiers using a test chamber
ISO 10121-3:2022 Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation — Part 3: Classification system for GPACDs applied to treatment of outdoor air
ISO/TS 19425:2015 Reciprocating internal combustion engines - Measurement method for air cleaners - Sound power level of combustion air inlet noise and insertion loss using sound pressure
IEC/DPAS 63086-3-1 Household and similar electrical air cleaning appliances — Methods for measuring the performance — Part 3-1: Particular requirements for reduction of microorganisms
IEC/CD 63086-2-2:2023 Household and similar electrical air cleaning appliances — Methods for measuring the performance — Part 2-2: Particular requirements for determination of gas-phase pollutant reduction

General Administration of Quality Supervision, Inspection and Quarantine of the People‘s Republic of China, foreign air purifiers

GB 21551.3-2010 Antibacterial and cleaning function for household and similar electrical appliances.Particular requirements of air cleaner
GB 4706.45-1999 Safety of household and similar electrical appliances Particular requirements for air-cleaning appliances
GB 4706.45-2008 Household and similar electric appliances.Safety.Particular requirements for air-cleaning appliances
GB/T 22766.9-2009 Household and similar electrical appliances.After-sales service.Part 9:Particular requirement for air cleaner

American Society for Testing and Materials (ASTM), foreign air purifiers

ASTM F1471-93(2001) Standard Test Method for Air Cleaning Performance of a High-Efficiency Particulate Air- Filter System
ASTM E2543-08 Standard Specification for Portable Air Heaters Used at Personnel Decontamination Stations and Shelters
ASTM E2543-08(2014) Standard Specification for Portable Air Heaters Used at Personnel Decontamination Stations and Shelters

Association Francaise de Normalisation, foreign air purifiers

NF X44-060:1993 Air cleaning equipment. Oil must gas purifiers with integral fan for screw-cutting industry. Test method.
NF X43-404-36*NF ISO 16000-36:2018 Indoor air - Part 36 : standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber
NF C73-865*NF EN 60335-2-65:2005 Household and similar electrical appliances - Safety - Part 2-65 : particular requirements for air-cleaning appliances
NF EN 60335-2-65/A12:2022 Appareils électrodomestiques et analogues - Sécurité - Partie 2-65 : Règles particulières pour les épurateurs d'air
NF EN 60335-2-65/A1:2008 Appareils électrodomestiques et analogues - Sécurité - Partie 2-65 : règles particulières pour les épurateurs d'air
NF EN 60335-2-65:2005 Appareils électrodomestiques et analogues - Sécurité - Partie 2-65 : règles particulières pour les épurateurs d'air
NF EN 60335-2-65/A2:2022 Appareils électrodomestiques et analogues - Sécurité - Partie 2 65 : Règles particulières pour les épurateurs d'air
NF EN 60335-2-65/A11:2013 Appareils électrodomestiques et analogues - Sécurité - Partie 2-65 : règles particulières pour les épurateurs d'air
NF ISO 16000-36:2018 Air intérieur - Partie 36 : méthode normalisée d'évaluation du taux d'abattement de bactéries cultivables aéroportées par des purificateurs d'air en utilisant une chambre d'essai
NF C73-865/A11*NF EN 60335-2-65/A11:2013 Household and similar electrical appliances - Safety - Part 2-65 : particular requirements for air-cleaning appliances
NF C73-865/A1*NF EN 60335-2-65/A1:2008 Household and similar electrical appliances - Safety - Part 2-65 : particular requirements for air-cleaning appliances
NF C20-540:1990 ENVIRONMENTAL TESTING. TEST METHODS. CLIMATIC AGEING TEST OF EQUIPMENT AND SYNTHETIC MATERIALS FOR OUTDOOR USE.

British Standards Institution (BSI), foreign air purifiers

PD IEC PAS 63086-3-1:2023 Household and similar electrical air cleaning appliances. Methods for measuring the performance. Method for assessing the reduction rate of key bioaerosols by portable air cleaners using an aerobiology test chamber
BS EN 60335-2-65:2003 Specification for safety of household and similar electrical appliances - Particular requirements for air-cleaning appliances
BS ISO 16000-36:2018 Indoor air - Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber
BS EN 60335-2-65:2003+A1:2008 Household and similar electrical appliances – Safety Part 2-65: Particular requirements for air-cleaning appliances
BS EN IEC 63086-1:2020 Household and similar electrical air cleaning appliances. Methods for measuring the performance. General requirements
BS EN 60335-2-65:2003+A12:2022 Household and similar electrical appliances. Safety - Particular requirements for air-cleaning appliances
22/30432789 DC BS ISO 16000-44. Indoor air - Part 44. Test method for measuring perceived indoor air quality for use in testing the performance of gas phase air cleaners
BS EN ISO 10121-3:2022 Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation - Classification system for GPACDs applied to treatment of outdoor air
BS EN 60335-2-65:2003+A11:2012 Household and similar electrical appliances. Safety. Particular requirements for air-cleaning appliances
14/30297046 DC BS EN 60335-2-65 AMD2. Household and similar electrical appliances. Safe ty. Particular requirements for air cleaning appliances
21/30429753 DC BS EN IEC 60704-2-19. Household and similar electrical appliances. Test code for the determination of airborne acoustical noise. Part 2-19. Particular requirements for air cleaners
21/30393132 DC BS EN ISO 10121-3. Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation. Part 3. Classification system for GPACDs applied to treatment of outdoor air
BS PD ISO/TS 19425:2015 Reciprocating internal combustion engines. Measurement method for air cleaners. Sound power level of combustion air inlet noise and insertion loss using sound pressure
BS ISO 22197-3:2011 Fine ceramics (advanced ceramics, advanced technical ceramics). Test method for air-purification performance of semiconducting photocatalytic materials. Removal of toluene
23/30468528 DC BS EN 60335-2-65 AMD 13. Household and similar electrical appliances. Safety - Part 2-65. Particular requirements for air-cleaning appliances
22/30442151 DC BS EN 60335-2-65. Household and similar electrical appliances. Safety. Part 2-65. Particular requirements for air-cleaning appliances
PD ISO/TS 19425:2015 Reciprocating internal combustion engines. Measurement method for air cleaners. Sound power level of combustion air inlet noise and insertion loss using sound pressure
22/30449535 DC BS EN 63086-1 AMD1. Household and similar electrical air cleaning appliances. Methods for measuring the performance. Part 1. General requirements
BS 8468-4:2020 Respiratory protective devices for use against chemical, biological, radiological and nuclear (CBRN) agents - Powered air purifying respirators. Specification
16/30332427 DC BS EN 60335-2-65 AMD AA. Household and similar electrical appliances. Safety. Part 2-65. Particular requirements for air-cleaning appliances
21/30402067 DC BS EN IEC 63086-2-1. Household and similar electrical air cleaning appliances. Methods for measuring the performance. Part 2-1. Particular requirements for determination of reduction of particles
19/30398491 DC BS 8468-4. Respiratory protective devices for use against chemical, biological, radiological and nuclear (CBRN) agents. Part 4. Powered air purifying respirators. Specification

Standard Association of Australia （SAA）, foreign air purifiers

AS/NZS 60335.2.65:2015
AS/NZS 3350.2.65/AMD 1:1998 Approval and test specification - Safety of household and similar electrical appliances Part 2.65: Particular requirements - Air-cleaning appliances

Professional Standard - Energy, foreign air purifiers

NB/T 20039.19-2013 Code on nuclear air and gas treatment Ventilation, air conditioning and air cleaning.Part 19: Special type HEPA filters

IX-IX-IEC, foreign air purifiers

IEC PAS 63086-3-1:2023 Household and similar electrical air cleaning appliances - Methods for measuring the performance - Part 3-1: Method for assessing the reduction rate of key bioaerosols by portable air cleaners using an aerobiology test chamber

International Electrotechnical Commission (IEC), foreign air purifiers

IEC PAS 62587:2008 Method for measuring performance of portable household electric room air cleaners
IEC 60335-2-65:2005 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65:2002 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65:2008 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65:2002/AMD2:2015 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65:2015 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65/AMD1:2000 Safety of household and similar electrical appliances - Part 2-65: Particular requirements for air-cleaning appliances; Amendment 1
IEC 60335-2-65:2002+AMD1:2008 CSV Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65:2002/AMD1:2008 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances; Amendment 1
IEC 60335-2-65:2002/COR1:2004 Corrigendum 1 - Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
IEC 60335-2-65:2002+AMD1:2008+AMD2:2015 CSV Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances

未注明发布机构, foreign air purifiers

BS ISO 16000-36:2018(2019) Indoor air Part 36 : Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber

German Institute for Standardization, foreign air purifiers

DIN ISO 16000-36:2019-07 Indoor air - Part 36: Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber (ISO 16000-36:2018, Corrected version 2019-03-01)
DIN ISO 16000-44:2022-05 Indoor air - Part 44: Test method for measuring perceived indoor air quality for use in testing the performance of gas phase air cleaners (ISO/DIS 16000-44:2022); Text in German and English / Note: Date of issue 2022-03-25
DIN EN ISO 10121-3:2021-08 Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation - Part 3: Classification system for GPACDs applied to treatment of outdoor air (ISO/DIS 10121-3:2021); German and English version prEN ISO 10...
DIN ISO 16000-36:2019 Indoor air - Part 36: Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber (ISO 16000-36:2018, Corrected version 2019-03-01)
DIN EN ISO 10121-3:2023-10 Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation - Part 3: Classification system for GPACDs applied to treatment of outdoor air (ISO 10121-3:2022); German version EN ISO 10121-3:2022
DIN EN 60335-2-65:2009 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances, (IEC 60335-2-65:2002 + Corrigendum 2004 + A1:2008); German version EN 60335-2-65:2003 + A1:2008

CENELEC - European Committee for Electrotechnical Standardization, foreign air purifiers

EN 60335-2-65:2003/fprAA:2015 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
EN 60335-2-65:1995 Safety of Household and Similar Electrical Appliances Part 2: Particular Requirements for Air-Cleaning Appliances

RU-GOST R, foreign air purifiers

GOST R 52161.2.65-2008 Safety of household and similar electrical appliances. Part 2.65. Particular requirements for air-cleaning appliances
GOST R ISO 16000-36-2021 Indoor air. Part 36. Standard method for assessing the reduction rate of culturable airborne bacteria by air purifiers using a test chamber
GOST R IEC 335-2-65-1996 Safety of household and similar electrical appliances. Particular requirements for air-cleaning appliances and test methods
GOST IEC 60335-2-65-2012 Safety of household and similar electrical appliances. Part 2-65. Particular requirements for air-cleaning appliances

Japanese Industrial Standards Committee (JISC), foreign air purifiers

JIS C 9335-2-65:2021 Household and similar electrical appliances -- Safety -- Part 2-65: Particular requirements for air-cleaning appliances
JIS C 9335-2-65 AMD 1:2023 Household and similar electrical appliances -- Safety -- Part 2-65: Particular requirements for air-cleaning appliances (Amendment 1)
JIS B 9908-2:2019 Test method of air filter units for ventilation and electric air cleaners for ventilation -- Part 2: Measurement of fractional efficiency and air flow resistance
JIS B 9908-4:2019 Test method of air filter units for ventilation and electric air cleaners for ventilation -- Part 4: Conditioning method to determine the minimum fractional test efficiency
JIS B 9908-3:2019 Test method of air filter units for ventilation and electric air cleaners for ventilation -- Part 3: Determination of the gravimetric efficiency and the air flow resistance versus the mass of test dust captured
JIS B 9908-1:2019 Test method of air filter units for ventilation and electric air cleaners for ventilation -- Part 1: Technical specifications, requirements and classification system based upon particulate matter efficiency

ES-UNE, foreign air purifiers

UNE-EN 60335-2-65:2005/A2:2023 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
UNE-EN 60335-2-65:2005/A12:2023 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
UNE-EN ISO 10121-3:2023 Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation - Part 3: Classification system for GPACDs applied to treatment of outdoor air (ISO 10121-3:2022)

VN-TCVN, foreign air purifiers

TCVN 5699-2-65-2010 Household and similar electrical appliances.Safety.Part 2-65:Particular requirements for air-cleaning appliances

AENOR, foreign air purifiers

UNE-EN 60335-2-65:2005 Household and similar electrical appliances - Safety -- Part 2-65: Particular requirements for air-cleaning appliances
UNE-EN 60335-2-65:2005/A11:2013 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
UNE-EN 60335-2-65:2005/A1:2008 Household and similar electrical appliances - Safety -- Part 2-65: Particular requirements for air-cleaning appliances

Danish Standards Foundation, foreign air purifiers

DS/EN 60335-2-65/A1:2008 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
DS/EN 60335-2-65/Corr.1:2004 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
DS/EN 60335-2-65:2003 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances
DS/EN 60335-2-65/A11:2012 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances

Lithuanian Standards Office , foreign air purifiers

LST EN 60335-2-65-2003/A11-2012 Household and similar electrical appliances - Safety -- Part 2-65: Particular requirements for air-cleaning appliances
LST EN 60335-2-65-2003 Household and similar electrical appliances. Safety. Part 2-65: Particular requirements for air-cleaning appliances (IEC 60335-2-65:2002)
LST EN 60335-2-65-2003/A1-2008 Household and similar electrical appliances - Safety - Part 2-65: Particular requirements for air-cleaning appliances (IEC 60335-2-65:2002/A1:2008)

European Committee for Standardization (CEN), foreign air purifiers

EN ISO 10121-3:2022 Test methods for assessing the performance of gas-phase air cleaning media and devices for general ventilation - Part 3: Classification system for GPACDs applied to treatment of outdoor air (ISO 10121-3:2022)

ZA-SANS, foreign air purifiers

SANS 60335-2-65:2003 Household and similar electrical appliances - Safety Part 2-65: Particular requirements for air-cleaning appliances
SANS 60335-2-65:2009 Household and similar electrical appliances - Safety Part 2-65: Particular requirements for air-cleaning appliances

US-CFR-file, foreign air purifiers

CFR 15-740.11-2014 Commerce and foreign trade. Part740:License exceptions. Section740.11:Governments, international organizations, international inspections under the Chemical Weapons Convention, and the International Space Station (GOV).
CFR 15-740.11-2013 Commerce and foreign trade. Part740:License exceptions. Section740.11:Governments, international organizations, international inspections under the Chemical Weapons Convention, and the International Space Station (GOV).

Canadian Standards Association (CSA), foreign air purifiers

CAN/CSA-E60335-2-65-2011 Household and similar electrical appliances — Safety — Part 2-65: Particular requirements for air-cleaning appliances (Second Edition)

European Committee for Electrotechnical Standardization（CENELEC）, foreign air purifiers

EN 60335-2-65:2003 Household and similar electrical appliances - Safety Part 2-65: Particular requirements for air-cleaning appliances (Incorporates Amendment A11: 2012)

SE-SIS, foreign air purifiers

SIS SS 433 07 88-1986 Safety of household and similar electrical appliances - Particular requirements for insect kil/ers and electrostatic air cleaners, ionization appliances and similar appliances working a t high voltage