Skip to content
Please enter a keyword to search

  • EN 14399-1:2015

    Current The latest, up-to-date edition.

    High-strength structural bolting assemblies for preloading - Part 1: General requirements

    Available format(s): 

    Language(s): 

    Published date:  18-02-2015

    Publisher:  Comite Europeen de Normalisation

    Pure ENs are not available for sale, please purchase a suitable national adoption

    Sorry this product is not available in your region.

    Add To Cart

    Table of Contents - (Show below) - (Hide below)

    Foreword
    Introduction
    1 Scope
    2 Normative references
    3 Terms and definitions
    4 Product characteristics
    5 Testing and assessment methods
    6 Assessment and Verification of Constancy of
      Performance (AVCP)
    Annex ZA (informative) - Clauses of this European Standard
             addressing the provisions of the
             EU Construction Products Regulation
    Bibliography

    Abstract - (Show below) - (Hide below)

    This European Standard specifies the general requirements for bolt/nut/washer(s) assemblies for high-strength structural bolting, which are suitable for preloading.The intended use of bolting assemblies in accordance with this European Standard is structural metallic works.NOTE 1High-strength structural bolting assemblies in accordance with EN 14399-2 to EN 14399-10 are designed to fulfil the requirements of this European Standard.NOTE 2High-strength structural bolting assemblies are suitable for preloading in accordance with EN 1090-2 in steel structures.High-strength structural bolting assemblies smaller than M12 are not designed to be preloaded.High-strength structural bolting assemblies are not designed to be welded.Railway rail fasteners are not covered by this standard.

    General Product Information - (Show below) - (Hide below)

    Committee CEN/TC 185
    Document Type Standard
    Publisher Comite Europeen de Normalisation
    Status Current

    Standards Referenced By This Book - (Show below) - (Hide below)

    02/704463 DC : DRAFT MAR 2002 PREN 14399-4 - HIGH-STRENGTH STRUCTURAL BOLTING FOR PRELOADING - PART 4: SYSTEM HV - HEXAGON BOLT AND NUT ASSEMBLIES
    02/704461 DC : DRAFT MAR 2002 PREN 14399-2 - HIGH-STRENGTH STRUCTURAL BOLTING FOR PRELOADING - PART 2: SUITABILITY TEST FOR PRELOADING
    02/704462 DC : DRAFT MAR 2002 PREN 14399-3 - HIGH-STRENGTH STRUCTURAL BOLTING FOR PRELOADING - PART 3: SYSTEM HR - HEXAGON BOLT AND NUT ASSEMBLIES
    DIN EN 14399-10 E : 2009 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    13/30277440 DC : 0 BS EN 14399-6 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 6: PLAIN CHAMFERED WASHERS
    PREN 1090-2 : DRAFT 2015 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    UNE-EN 1993-1-8:2013 Eurocode 3: Design of steel structures - Part 1-8: Design of joints
    PREN 14399-8 : DRAFT 2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 8: SYSTEM HV - HEXAGON FIT BOLT AND NUT ASSEMBLIES
    EN 14399-8:2007 High-strength structural bolting assemblies for preloading - Part 8: System HV - Hexagon fit bolt and nut assemblies
    UNI EN 14399-7 : 2008 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 7: SYSTEM HR - COUNTERSUNK HEAD BOLT AND NUT ASSEMBLIES
    EN 15048-1:2016 Non-preloaded structural bolting assemblies - Part 1: General requirements
    DIN EN 14399-2:2015-04 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 2: SUITABILITY FOR PRELOADING
    BS EN 14399-5 : 2015-02 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 5: PLAIN WASHERS
    DIN EN 1090-2:2011-10 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    DIN EN 14399-8:2008-03 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 8: SYSTEM HV - HEXAGON FIT BOLT AND NUT ASSEMBLIES
    13/30277434 DC : 0 BS EN 14399-4 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 4: SYSTEM HV - HEXAGON BOLT AND NUT ASSEMBLIES
    07/30107797 DC : 0 BS EN 14399-9 - HIGH STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 9: SYSTEM HR OR HV - BOLT AND NUT ASSEMBLIES WITH DIRECT TENSION INDICATORS
    07/30166055 DC : 0 BS EN 14399-10 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    PREN 14399-2 : DRAFT 2013 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 2: SUITABILITY TEST FOR PRELOADING
    PREN 14399-5 : DRAFT 2013 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 5: PLAIN WASHERS
    02/704464 DC : DRAFT MAR 2002 PREN 14399-5 - HIGH-STRENGTH STRUCTURAL BOLTING FOR PRELOADING - PART 5: PLAIN WASHERS FOR SYSTEM HR
    I.S. EN 14399-10:2009 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    DIN EN 14399-8:2016-01 (Draft) HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 8: SYSTEM HV - HEXAGON FIT BOLT AND NUT ASSEMBLIES
    UNE-EN 14399-4:2016 High-strength structural bolting assemblies for preloading - Part 4: System HV - Hexagon bolt and nut assemblies
    UNE-EN 14399-6:2016 High-strength structural bolting assemblies for preloading - Part 6: Plain chamfered washers
    PREN 14399-10 : DRAFT 2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    UNE-EN 15048-1:2018 Non-preloaded structural bolting assemblies - Part 1: General requirements
    UNI EN 14399-10 : 2009 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    UNI EN 14399-9 : 2009 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 9: SYSTEM HR OR HV - DIRECT TENSION INDICATORS FOR BOLT AND NUT ASSEMBLIES
    ONORM EN 14399-10 : JUN 2009 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    DIN EN 14399-9:2016-01 (Draft) HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 9: SYSTEM HR OR HV - DIRECT TENSION INDICATORS FOR BOLT AND NUT ASSEMBLIES
    BS EN 1090-2 : 2008 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    EN 14399-10:2018 High-strength structural bolting assemblies for preloading - Part 10: System HRC - Bolt and nut assemblies with calibrated preload
    UNI EN 1090-2 : 2011 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    DIN EN 1993-1-8:2010-12 Eurocode 3: Design of steel structures - Part 1-8: Design of joints (includes Corrigendum AC:2009)
    BS EN 15048-1:2007 Non-preloaded structural bolting assemblies General requirements
    I.S. EN 14399-3:2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 3: SYSTEM HR - HEXAGON BOLT AND NUT ASSEMBLIES
    I.S. EN 14399-4:2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 4: SYSTEM HV - HEXAGON BOLT AND NUT ASSEMBLIES
    I.S. EN 14399-6:2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 6: PLAIN CHAMFERED WASHERS
    I.S. EN 14399-5:2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 5: PLAIN WASHERS
    DIN EN 14399-3:2015-04 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 3: SYSTEM HR - HEXAGON BOLT AND NUT ASSEMBLIES
    I.S. EN 14399-2:2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 2: SUITABILITY FOR PRELOADING
    13/30277437 DC : 0 BS EN 14399-5 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 5: PLAIN WASHERS
    13/30277431 DC : 0 BS EN 14399-3 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 3: SYSTEM HR - HEXAGON BOLT AND NUT ASSEMBLIES
    PREN 14399-9 : DRAFT 2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 9: SYSTEM HR OR HV - DIRECT TENSION INDICATORS FOR BOLT AND NUT ASSEMBLIES
    15/30332551 DC : 0 BS EN 14399-10 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    DIN EN 14399-10:2016-01 (Draft) HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 10: SYSTEM HRC - BOLT AND NUT ASSEMBLIES WITH CALIBRATED PRELOAD
    PREN 14399-3 : DRAFT 2013 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 3: SYSTEM HR - HEXAGON BOLT AND NUT ASSEMBLIES
    PREN 14399-6 : DRAFT 2013 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 6: PLAIN CHAMFERED WASHERS
    UNE-EN 1090-2:2011 Execution of steel structures and aluminium structures - Part 2: Technical requirements for steel structures
    EN 14399-7:2007 High-strength structural bolting assemblies for preloading - Part 7: System HR - Countersunk head bolt and nut assemblies
    DIN EN 1090-2:2015-07 (Draft) EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    UNI EN 1993-1-8 : 2005 EUROCODE 3 - DESIGN OF STEEL STRUCTURES - PART 1-8: DESIGN OF JOINTS
    13/30277428 DC : 0 BS EN 14399-2 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 2: SUITABILITY TEST FOR PRELOADING
    02/704465 DC : DRAFT MAR 2002 PREN 14399-6 - HIGH-STRENGTH STRUCTURAL BOLTING FOR PRELOADING - PART 6: PLAIN CHAMFERED WASHERS FOR SYSTEMS HR AND HV
    UNE-EN 14399-5:2016 High-strength structural bolting assemblies for preloading - Part 5: Plain washers
    BS EN 14399-7:2007 High-strength structural bolting assemblies for preloading System HR. Countersunk head bolt and nut assemblies
    NF EN 1090-2 : 2009 + A1 2011 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    BS EN 14399-10:2009 High-strength structural bolting assemblies for preloading System HRC. Bolt and nut assemblies with calibrated preload
    15/30332548 DC : 0 BS EN 14399-8 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 8: SYSTEM HV - HEXAGON FIT BOLT AND NUT ASSEMBLIES
    EN 1090-2:2008+A1:2011 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    I.S. EN 15048-1:2016 NON-PRELOADED STRUCTURAL BOLTING ASSEMBLIES - PART 1: GENERAL REQUIREMENTS
    DIN EN 15048-1:2016-09 NON-PRELOADED STRUCTURAL BOLTING ASSEMBLIES - PART 1: GENERAL REQUIREMENTS
    BS EN 14399-6:2005 High-strength structural bolting assemblies for preloading Plain chamfered washers
    BS EN 14399-3:2015 High-strength structural bolting assemblies for preloading System HR. Hexagon bolt and nut assemblies
    BS EN 1993-1-8:2005 Eurocode 3. Design of steel structures Design of joints
    BS EN 14399-4:2005 High-strength structural bolting assemblies for preloading System HV. Hexagon bolt and nut assemblies
    EN 14399-2:2015 High-strength structural bolting assemblies for preloading - Part 2: Suitability for preloading
    EN 14399-9:2018 High-strength structural bolting assemblies for preloading - Part 9: System HR or HV - Direct tension indicators for bolt and nut assemblies
    EN 1993-1-8:2005/AC:2009 EUROCODE 3: DESIGN OF STEEL STRUCTURES - PART 1-8: DESIGN OF JOINTS
    EN 14399-5:2015 High-strength structural bolting assemblies for preloading - Part 5: Plain washers
    EN 14399-4:2015 High-strength structural bolting assemblies for preloading - Part 4: System HV - Hexagon bolt and nut assemblies
    EN 14399-3:2015 High-strength structural bolting assemblies for preloading - Part 3: System HR - Hexagon bolt and nut assemblies
    EN 14399-6:2015 High-strength structural bolting assemblies for preloading - Part 6: Plain chamfered washers
    15/30332545 DC : 0 BS EN 14399-7 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 7: SYSTEM HR - COUNTERSUNK HEAD BOLT AND NUT ASSEMBLIES
    PREN 14399-4 : DRAFT 2013 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 4: SYSTEM HV - HEXAGON BOLT AND NUT ASSEMBLIES
    BS EN 14399-8:2007 High-strength structural bolting assemblies for preloading System HV. Hexagon fit bolt and nut assemblies
    15/30332554 DC : 0 BS EN 14399-9 - HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 9: SYSTEM HR OR HV - DIRECT TENSION INDICATORS FOR BOLT AND NUT ASSEMBLIES
    UNE-EN 14399-3:2016 High-strength structural bolting assemblies for preloading - Part 3: System HR - Hexagon bolt and nut assemblies
    15/30320416 DC : 0 BS EN 1090-2 - EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    PREN 14399-7 : DRAFT 2015 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 7: SYSTEM HR - COUNTERSUNK HEAD BOLT AND NUT ASSEMBLIES
    UNE-EN 14399-2:2016 High-strength structural bolting assemblies for preloading - Part 2: Suitability for preloading
    I.S. EN 1090-2:2008 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    I.S. EN 14399-7:2007 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 7: SYSTEM HR - COUNTERSUNK HEAD BOLT AND NUT ASSEMBLIES
    UNI EN 14399-8 : 2008 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 8: SYSTEM HV - HEXAGON FIT BOLT AND NUT ASSEMBLIES
    BS EN 14399-9:2009 High strength structural bolting for preloading System HR or HV. Direct tension indicators for bolt and nut assemblies
    DIN EN 14399-7:2016-01 (Draft) HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 7: SYSTEM HR - COUNTERSUNK HEAD BOLT AND NUT ASSEMBLIES
    I.S. EN 14399-8:2007 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 8: SYSTEM HV - HEXAGON FIT BOLT AND NUT ASSEMBLIES
    I.S. EN 14399-9:2009 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 9: SYSTEM HR OR HV - DIRECT TENSION INDICATORS FOR BOLT AND NUT ASSEMBLIES
    DIN EN 14399-5:2015-04 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 5: PLAIN WASHERS
    DIN EN 14399-4:2015-04 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 4: SYSTEM HV - HEXAGON BOLT AND NUT ASSEMBLIES
    DIN EN 14399-6:2015-04 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 6: PLAIN CHAMFERED WASHERS
    BS EN 14399-2 : 2015-02 HIGH-STRENGTH STRUCTURAL BOLTING ASSEMBLIES FOR PRELOADING - PART 2: SUITABILITY FOR PRELOADING

    Standards Referencing This Book - (Show below) - (Hide below)

    ISO 6507-1:2005 Metallic materials Vickers hardness test Part 1: Test method
    EN 14399-8:2007 High-strength structural bolting assemblies for preloading - Part 8: System HV - Hexagon fit bolt and nut assemblies
    ISO 898-2:2012 Mechanical properties of fasteners made of carbon steel and alloy steel — Part 2: Nuts with specified property classes — Coarse thread and fine pitch thread
    EN ISO 6508-1:2016 Metallic materials - Rockwell hardness test - Part 1: Test method (ISO 6508-1:2016)
    EN 14399-3:2015 High-strength structural bolting assemblies for preloading - Part 3: System HR - Hexagon bolt and nut assemblies
    ISO 4759-3:2016 Tolerances for fasteners Part 3: Washers for bolts, screws and nuts Product grades A, C and F
    ISO 10684:2004 Fasteners — Hot dip galvanized coatings
    ISO 965-5:1998 ISO general purpose metric screw threads — Tolerances — Part 5: Limits of sizes for internal screw threads to mate with hot-dip galvanized external screw threads with maximum size of tolerance position h before galvanizing
    ISO 4759-1:2000 Tolerances for fasteners — Part 1: Bolts, screws, studs and nuts — Product grades A, B and C
    305/2011 : 2011 AMD 2 2014 REGULATION (EU) NO 305/2011 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL OF 9 MARCH 2011 LAYING DOWN HARMONISED CONDITIONS FOR THE MARKETING OF CONSTRUCTION PRODUCTS AND REPEALING COUNCIL DIRECTIVE 89/106/EEC (TEXT WITH EEA RELEVANCE)
    ISO 6508-1:2016 Metallic materials — Rockwell hardness test — Part 1: Test method
    EN ISO 4759-3:2016 Tolerances for fasteners - Part 3: Washers for bolts, screws and nuts - Product grades A, C and F (ISO 4759-3:2016)
    ISO 965-2:1998 ISO general purpose metric screw threads — Tolerances — Part 2: Limits of sizes for general purpose external and internal screw threads — Medium quality
    EN ISO 4759-1 : 2000 TOLERANCES FOR FASTENERS - PART 1: BOLTS, SCREWS, STUDS AND NUTS - PRODUCT GRADES A, B AND C
    EN ISO 9001:2015 Quality management systems - Requirements (ISO 9001:2015)
    EN 14399-6:2015 High-strength structural bolting assemblies for preloading - Part 6: Plain chamfered washers
    ISO 888:2012 Fasteners — Bolts, screws and studs — Nominal lengths and thread lengths
    EN 10204:2004 Metallic products - Types of inspection documents
    EN ISO 225:2010 Fasteners - Bolts, screws, studs and nuts - Symbols and descriptions of dimensions (ISO 225:2010)
    ISO 9001:2015 Quality management systems — Requirements
    EN 14399-4:2015 High-strength structural bolting assemblies for preloading - Part 4: System HV - Hexagon bolt and nut assemblies
    EN ISO 898-1:2013 Mechanical properties of fasteners made of carbon steel and alloy steel - Part 1: Bolts, screws and studs with specified property classes - Coarse thread and fine pitch thread (ISO 898-1:2013)
    EN 1090-2:2008+A1:2011 EXECUTION OF STEEL STRUCTURES AND ALUMINIUM STRUCTURES - PART 2: TECHNICAL REQUIREMENTS FOR STEEL STRUCTURES
    EN 14399-7:2007 High-strength structural bolting assemblies for preloading - Part 7: System HR - Countersunk head bolt and nut assemblies
    EN ISO 10684:2004/AC:2009 Fasteners - Hot dip galvanized coatings (ISO 10684:2004/Cor 1:2008)
    EN 14399-5:2015 High-strength structural bolting assemblies for preloading - Part 5: Plain washers
    EN 14399-2:2015 High-strength structural bolting assemblies for preloading - Part 2: Suitability for preloading
    ISO 898-1:2013 Mechanical properties of fasteners made of carbon steel and alloy steel — Part 1: Bolts, screws and studs with specified property classes — Coarse thread and fine pitch thread
    View more information

    • Access your standards online with a subscription

      Features

      • Simple online access to standards, technical information and regulations
      • Critical updates of standards and customisable alerts and notifications
      • Multi - user online standards collection: secure, flexibile and cost effective