• Shopping Cart
    There are no items in your cart

EN 771-2:2011+A1:2015

Current

Current

The latest, up-to-date edition.

Specification for masonry units - Part 2: Calcium silicate masonry units

Published date

08-19-2015

Sorry this product is not available in your region.

European foreword
1 Scope
2 Normative references
3 Terms and definitions
4 Materials and manufacture
5 Requirements for calcium silicate masonry units
6 Description, designation, designation code and
  classification of calcium silicate masonry units
7 Marking
8 Assessment and verification of constancy of
  performance (AVCP)
Annex A (normative) - Sampling for product type
        determination tests and for independent
        testing of consignments
Annex B (normative) - Cutting schemes
Annex C (normative) - Tolerances on accessory units
Annex D (informative) - Classification systems
Annex E (informative) - Guidance for test frequencies
        for designing a FPC system to demonstrate
        conformity of finished products with the requirements
        of the standard and the declaration of the manufacturer
Annex ZA (informative) - Clauses of this European
         Standard addressing the provisions of the EU
         Construction Products Regulation
Bibliography

This European Standard specifies the characteristics and performance requirements of calcium silicate masonry units for which the main intended uses are inner walls, outer walls, cellars, foundations and external chimney masonry.This European Standard is intended to apply to all calcium silicate masonry units, including those of an overall nonrectangular parallelepiped shape, specially shaped and accessory units.It defines the performance related to e.g. strength, density and dimensional accuracy, measured according to the corresponding test methods contained in separate European Standards.It provides for the !assessment and verification of constancy of performance (AVCP)" of the product to this European Standard. The marking requirement for products covered by this document is also included.This European Standard does not specify standard sizes for calcium silicate masonry units, nor standard work dimensions and angles of specially shaped and accessory units.It does not cover units with more than 60 % volume of voids, nor products made from shale as a major raw material.It does not cover storey height panels.It does not cover units intended for use as a damp proof course, nor units with an incorporated thermal insulation material bonded to the faces of the unit susceptible to be exposed to fire, nor chimney flue units.

Committee
CEN/TC 125
DevelopmentNote
2011 Edition Re-Issued in August 2015 & incorporates AMD 1 2015. (08/2015)
DocumentType
Standard
PublisherName
Comite Europeen de Normalisation
Status
Current

I.S. EN 1996-1-2:2005 EUROCODE 6 - DESIGN OF MASONRY STRUCTURES - PART 1-2: GENERAL RULES - STRUCTURAL FIRE DESIGN (INCLUDING IRISH NATIONAL ANNEX)
CEN/TR 16886:2016 Guidance on the application of statistical methods for determining the properties of masonry products
10/30212126 DC : 0 BS EN 845-2 - SPECIFICATION FOR ANCILLARY COMPONENTS FOR MASONRY - PART 2: LINTELS
I.S. EN 15080-12:2011 EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - PART 12: LOADBEARING MASONRY WALLS
DIN EN 771-6:2015-11 SPECIFICATION FOR MASONRY UNITS - PART 6: NATURAL STONE MASONRY UNITS
DIN EN 772-2:2005-05 METHODS OF TEST FOR MASONRY UNITS - PART 2: DETERMINATION OF PERCENTAGE AREA OF VOIDS IN MASONRY UNITS (BY PAPER INDENTATION)
DIN EN 1996-1-2:2011-04 Eurocode 6: Design of masonry structures - Part 1-2: General rules - Structural fire design (includes Corrigendum AC:2010)
BS EN 1015-9:1999 Methods of test for mortar for masonry Determination of workable life and correction time of fresh mortar
BS EN 846-8:2000 Methods of test for ancillary components for masonry Determination of load capacity and load-deflection characteristics of joist hangers
BS EN 772-13:2000 Methods of test for masonry units Determination of net and gross dry density of masonry units (except for natural stone)
DIN EN 15254-2:2009-10 EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - NON-LOADBEARING WALLS - PART 2: MASONRY AND GYPSUM BLOCKS
DIN EN 15287-2:2008-06 Chimneys - Design, installation and commissioning of chimneys - Part 2: Chimneys for roomsealed appliances
DIN EN 772-21:2011-07 Methods of test for masonry units - Part 21: Determination of water absorption of clay and calcium silicate masonry units by cold water absorption
10/30215389 DC : 0 BS EN 772-21 - METHODS OF TEST FOR MASONRY UNITS - PART 21: DETERMINATION OF WATER ABSORPTION OF CLAY AND CALCIUM SILICATE MASONRY UNITS BY COLD WATER ABSORPTION
PREN 772-16 : DRAFT 2010 METHODS OF TEST FOR MASONRY UNITS - PART 16: DETERMINATION OF DIMENSIONS
UNI EN 15080-12 : 2011 EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - PART 12: LOADBEARING MASONRY WALLS
UNI EN 772-21 : 2011 METHODS OF TEST FOR MASONRY UNITS - PART 21: DETERMINATION OF WATER ABSORPTION OF CLAY AND CALCIUM SILICATE MASONRY UNITS BY COLD WATER ABSORPTION
NF EN 772-21 : 2011 METHODS OF TEST FOR MASONRY UNITS - PART 21: DETERMINATION OF WATER ABSORPTION OF CLAY AND CALCIUM SILICATE MASONRY UNITS BY COLD WATER ABSORPTION
UNI EN 15287-2 : 2008 CHIMNEYS - DESIGN, INSTALLATION AND COMMISSIONING OF CHIMNEYS - PART 2: CHIMNEYS FOR ROOM-SEALED APPLIANCES
PREN 772-18 : DRAFT 2010 METHODS OF TEST FOR MASONRY UNITS - PART 18: DETERMINATION OF FREEZE-THAW RESISTANCE OF CALCIUM SILICATE MASONRY UNITS
UNE-EN 15080-12:2011 Extended application of results from fire resistance tests - Part 12: Loadbearing masonry walls
DIN EN 772-11:2011-07 Methods of test for masonry units - Part 11: Determination of water absorption of aggregate concrete, autoclaved aerated concrete, manufactured stone and natural stone masonry units due to capillary action and the initial rate of water absorption of clay masonry units
DIN EN 772-20:2005-05 METHODS OF TEST FOR MASONRY UNITS - PART 20: DETERMINATION OF FLATNESS OF FACES OF MASONRY UNITS
DIN EN 772-16:2011-07 Methods of test for masonry units - Part 16: Determination of dimensions
DIN EN 772-18:2011-07 Methods of test for masonry units - Part 18: Determination of freeze-thaw resistance of calcium silicate masonry units
BS EN 772-1 : 2011 METHODS OF TEST FOR MASONRY UNITS - PART 1: DETERMINATION OF COMPRESSIVE STRENGTH
I.S. EN 771-6:2011 SPECIFICATION FOR MASONRY UNITS - PART 6: NATURAL STONE MASONRY UNITS
I.S. EN 772-1:2011 METHODS OF TEST FOR MASONRY UNITS - PART 1: DETERMINATION OF COMPRESSIVE STRENGTH
I.S. EN 772-16:2011 METHODS OF TEST FOR MASONRY UNITS - PART 16: DETERMINATION OF DIMENSIONS
DIN EN 1996-1-1:2013-02 Eurocode 6: Design of masonry structures - Part 1-1: General rules for reinforced and unreinforced masonry structures (includes Amendment 1:2012)
I.S. EN 846-7:2012 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 7: DETERMINATION OF SHEAR LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF SHEAR TIES AND SLIP TIES (COUPLET TEST FOR MORTAR JOINT CONNECTIONS)
DIN EN 772-1:2000-09 METHODS OF TEST FOR MASONRY UNITS - PART 1: DETERMINATION OF COMPRESSIVE STRENGTH
I.S. EN 772-11:2011 METHODS OF TEST FOR MASONRY UNITS - PART 11: DETERMINATION OF WATER ABSORPTION OF AGGREGATE CONCRETE, AUTOCLAVED AERATED CONCRETE, MANUFACTURED STONE AND NATURAL STONE MASONRY UNITS DUE TO CAPILLARY ACTION AND THE INITIAL RATE OF WATER ABSORPTION OF CLAY MASONRY UNITS
I.S. EN 846-5:2012 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 5: DETERMINATION OF TENSILE AND COMPRESSIVE LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF WALL TIES (COUPLET TEST)
I.S. EN 846-6:2012 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 6 - DETERMINATION OF TENSILE AND COMPRESSIVE LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF WALL TIES (SINGLE END TEST)
DIN EN 772-9:2005-05 METHODS OF TEST FOR MASONRY UNITS - PART 9: DETERMINATION OF VOLUME AND PERCENTAGE OF VOIDS AND NET VOLUME OF CLAY AND CALCIUM SILICATE MASONRY UNITS BY SAND FILLING
DIN EN 1015-9:2007-05 Methods of test for mortar for masonry - Part 9: Determination of workable life and correction time of fresh mortar (includes Amendment A1:2006)
I.S. EN 1996-1-1:2005 EUROCODE 6 - DESIGN OF MASONRY STRUCTURES - PART 1-1: GENERAL RULES FOR REINFORCED AND UNREINFORCED MASONRY STRUCTURES (INCLUDING IRISH NATIONAL ANNEX)
I.S. EN 772-18:2011 METHODS OF TEST FOR MASONRY UNITS - PART 18: DETERMINATION OF FREEZE-THAW RESISTANCE OF CALCIUM SILICATE MASONRY UNITS
BS EN 15287-2:2008 Chimneys. Design, installation and commissioning of chimneys Chimneys for roomsealed appliances
BS EN 15254-2:2009 Extended application of results from fire resistance tests. Nonloadbearing walls Masonry and gypsum blocks
UNE-EN 1996-1-2:2011 Eurocode 6 - Design of masonry structures - Part 1-2: General rules - Structural fire design
05/30136031 DC : 0 EN 15287-1 - CHIMNEYS - DESIGN, INSTALLATION AND COMMISSIONING OF CHIMNEYS - PART 1: CHIMNEYS FOR NON-ROOMSEALED HEATING APPLIANCES
DIN EN 15080-12:2011-04 Extended application of results from fire resistance tests - Part 12: Loadbearing masonry walls
I.S. EN 772-21:2011 METHODS OF TEST FOR MASONRY UNITS - PART 21: DETERMINATION OF WATER ABSORPTION OF CLAY AND CALCIUM SILICATE MASONRY UNITS BY COLD WATER ABSORPTION
UNI EN 15254-2 : 2009 EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - NON-LOADBEARING WALLS - PART 2: MASONRY AND GYPSUM BLOCKS
PREN 772-11 : DRAFT 2010 METHODS OF TEST FOR MASONRY UNITS - PART 11: DETERMINATION OF WATER ABSORPTION OF AGGREGATE CONCRETE, AUTOCLAVED AERATED CONCRETE, MANUFACTURED STONE AND NATURAL STONE MASONRY UNITS DUE TO CAPILLARY ACTION AND THE INITIAL RATE OF WATER ABSORPTION OF CLAY MASONRY UNITS
DIN EN 1996-3:2010-12 Eurocode 6: Design of masonry structures - Part 3: Simplified calculation methods for unreinforced masonry structures (includes Corrigendum AC:2009)
BS EN 772-20:2000 Methods of test for masonry units Determination of flatness of faces of masonry units
UNE-EN 846-5:2013 Methods of test for ancillary components for masonry - Part 5: Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (couplet test)
UNE-EN 771-6:2012 Specification for masonry units - Part 6: Natural stone masonry units
EN 771-6:2011+A1:2015 Specification for masonry units - Part 6: Natural stone masonry units
EN 846-6:2012 Methods of test for ancillary components for masonry - Part 6: Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (single end test)
UNI EN 772-18 : 2011 METHODS OF TEST FOR MASONRY UNITS - PART 18: DETERMINATION OF FREEZE-THAW RESISTANCE OF CALCIUM SILICATE MASONRY UNITS
UNI EN 846-7 : 2012 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 7: DETERMINATION OF SHEAR LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF SHEAR TIES AND SLIP TIES (COUPLET TEST FOR MORTAR JOINT CONNECTIONS)
UNI EN 846-6 : 2012 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 6: DETERMINATION OF TENSILE AND COMPRESSIVE LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF WALL TIES (SINGLE END TEST)
UNI EN 846-5 : 2012 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 5: DETERMINATION OF TENSILE AND COMPRESSIVE LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF WALL TIES (COUPLET TEST)
UNI EN 1996-1-2 : 2005 EUROCODE 6 - DESIGN OF MASONRY STRUCTURES - PART 1-2: GENERAL RULES - STRUCTURAL FIRE DESIGN
UNI EN 772-11 : 2011 METHODS OF TEST FOR MASONRY UNITS - PART 11: DETERMINATION OF WATER ABSORPTION OF AGGREGATE CONCRETE, AUTOCLAVED AERATED CONCRETE, MANUFACTURED STONE AND NATURAL STONE MASONRY UNITS DUE TO CAPILLARY ACTION AND THE INITIAL RATE OF WATER ABSORPTION OF CLAY MASONRY UNITS
UNI EN 1996-1-1 : 2013 EUROCODE 6 - DESIGN OF MASONRY STRUCTURES - PART 1-1: GENERAL RULES FOR REINFORCED AND UNREINFORCED MASONRY STRUCTURES
UNI EN 772-16 : 2011 METHODS OF TEST FOR MASONRY UNITS - PART 16: DETERMINATION OF DIMENSIONS
10/30215380 DC : 0 BS EN 772-11 - METHODS OF TEST FOR MASONRY UNITS - PART 11: DETERMINATION OF WATER ABSORPTION OF AGGREGATE CONCRETE, AUTOCLAVED AERATED CONCRETE, MANUFACTURED STONE AND NATURAL STONE MASONRY UNITS DUE TO CAPILLARY ACTION AND THE INITIAL RATE OF WATER ABSORPTION OF CLAY MASONRY UNITS
I.S. EN 1996-3:2006 EUROCODE 6 - DESIGN OF MASONRY STRUCTURES - PART 3: SIMPLIFIED CALCULATION METHODS FOR UNREINFORCED MASONRY STRUCTURES (INCLUDING IRISH NATIONAL ANNEX)
07/30172842 DC : 0 BS EN 15080-12 - EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - PART 12: LOADBEARING MASONRY WALLS
10/30215386 DC : 0 BS EN 772-18 - METHODS OF TEST FOR MASONRY UNITS - PART 18: DETERMINATION OF FREEZE-THAW RESISTANCE OF CALCIUM SILICATE MASONRY UNIT
BS EN 15080-12:2011 Extended application of results from fire resistance tests Loadbearing masonry walls
05/30134891 DC : 0 EN 15254-2 - EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - NON-LOADBEARING WALLS - PART 2: MASONRY AND GYPSUM BLOCKS
10/30215383 DC : 0 BS EN 772-16 - METHODS OF TEST FOR MASONRY UNITS - PART 16: DETERMINATION OF DIMENSIONS
PD CEN/TR 16886:2016 Guidance on the application of statistical methods for determining the properties of masonry products
S.R. CEN/TR 16886:2016 GUIDANCE ON THE APPLICATION OF STATISTICAL METHODS FOR DETERMINING THE PROPERTIES OF MASONRY PRODUCTS
I.S. EN 15287-2:2008 CHIMNEYS - DESIGN, INSTALLATION AND COMMISSIONING OF CHIMNEYS - PART 2: CHIMNEYS FOR ROOMSEALED APPLIANCES
I.S. ENV 1996-1-2:1995 EUROCODE 6: DESIGN OF MASONRY STRUCTURES - PART 1-2: GENERAL RULES - STRUCTURAL FIRE DESIGN
BS EN 772-18:2011 Methods of test for masonry units Determination of freeze-thaw resistance of calcium silicate masonry units
BS EN 772-2:1998 Methods of test for masonry units Determination of percentage area of voids in masonry units (by paper indentation)
BS EN 771-6 : 2011 SPECIFICATION FOR MASONRY UNITS - PART 6: NATURAL STONE MASONRY UNITS
UNE-EN 846-6:2015 Methods of test for ancillary components for masonry - Part 6: Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (single end test)
BS EN 772-9:1998 Methods of test for masonry units Determination of volume and percentage of voids and net volume of clay and calcium silicate masonry units by sand filling
BS EN 846-5:2012 Methods of test for ancillary components for masonry Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (couplet test)
BS EN 1996-1-1 : 2005 EUROCODE 6 - DESIGN OF MASONRY STRUCTURES - PART 1-1: GENERAL RULES FOR REINFORCED AND UNREINFORCED MASONRY STRUCTURES
BS EN 846-6:2012 Methods of test for ancillary components for masonry Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (single end test)
BS EN 846-7:2012 Methods of test for ancillary components for masonry Determination of shear load capacity and load displacement characteristics of shear ties and slip ties (couplet test for mortar joint connections)
UNE-EN 846-7:2015 Methods of test for ancillary components for masonry - Part 7: Determination of shear load capacity and load displacement characteristics of shear ties and slip ties (couplet test for mortar joint connections)
BS EN 772-16:2011 Methods of test for masonry units Determination of dimensions
EN 772-1:2011+A1:2015 Methods of test for masonry units - Part 1: Determination of compressive strength
EN 772-16:2011 Methods of test for masonry units - Part 16: Determination of dimensions
EN 846-7:2012 Methods of test for ancillary components for masonry - Part 7: Determination of shear load capacity and load displacement characteristics of shear ties and slip ties (couplet test for mortar joint connections)
EN 1996-1-1:2005+A1:2012 Eurocode 6 - Design of masonry structures - Part 1-1: General rules for reinforced and unreinforced masonry structures
EN 772-13:2000 Methods of test for masonry units - Part 13: Determination of net and gross dry density of masonry units (except for natural stone)
EN 15287-2:2008 Chimneys - Design, installation and commissioning of chimneys - Part 2: Chimneys for roomsealed appliances
ENV 1996-1-2 : 1995 EUROCODE 6: DESIGN OF MASONRY STRUCTURES - PART 1-2: GENERAL RULES - STRUCTURAL FIRE DESIGN
EN 772-21:2011 Methods of test for masonry units - Part 21: Determination of water absorption of clay and calcium silicate masonry units by cold water absorption
EN 15254-2:2009 Extended application of results from fire resistance tests - Non-loadbearing walls - Part 2: Masonry and Gypsum Blocks
EN 846-5:2012 Methods of test for ancillary components for masonry - Part 5: Determination of tensile and compressive load capacity and load displacement characteristics of wall ties (couplet test)
EN 772-11:2011 Methods of test for masonry units - Part 11: Determination of water absorption of aggregate concrete, autoclaved aerated concrete, manufactured stone and natural stone masonry units due to capillary action and the initial rate of water absorption of clay masonry units
EN 772-18:2011 Methods of test for masonry units - Part 18: Determination of freeze-thaw resistance of calcium silicate masonry units
EN 15080-12:2011 Extended application of results from fire resistance tests - Part 12: Loadbearing masonry walls
BS EN 772-21:2011 Methods of test for masonry units Determination of water absorption of clay and calcium silicate masonry units by cold water absorption
UNE-EN 1996-1-1:2011 Eurocode 6 - Design of masonry structures - Part 1-1: General rules for reinforced and unreinforced masonry structures
DIN V 106:2005-10 CALCIUM SILICATE UNITS WITH SPECIFIC PROPERTIES
UNE-EN 15254-2:2010 Extended application of results from fire resistance tests - Non-loadbearing walls - Part 2: Masonry and Gypsum Blocks
I.S. EN 15254-2:2009 EXTENDED APPLICATION OF RESULTS FROM FIRE RESISTANCE TESTS - NONLOADBEARING WALLS - PART 2: MASONRY AND GYPSUM BLOCKS
DIN EN 772-1:2016-05 METHODS OF TEST FOR MASONRY UNITS - PART 1: DETERMINATION OF COMPRESSIVE STRENGTH
BS EN 772-11:2000 Methods of test for masonry units Determination of water absorption of aggregate concrete, manufactured stone and natural stone masonry units due to capillary action and the initial rate of water absorption of clay masonry units
BS EN 1996-3:2006 Eurocode 6. Design of masonry structures Simplified calculation methods for unreinforced masonry structures
BS EN 1996-1-2:2005 Eurocode 6. Design of masonry structures General rules. Structural fire design
DIN EN 846-7:2012-11 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 7: DETERMINATION OF SHEAR LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF SHEAR TIES AND SLIP TIES (COUPLET TEST FOR MORTAR JOINT CONNECTIONS)
DIN EN 846-5:2012-11 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 5: DETERMINATION OF TENSILE AND COMPRESSIVE LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF WALL TIES (COUPLET TEST)
DIN EN 846-6:2012-11 METHODS OF TEST FOR ANCILLARY COMPONENTS FOR MASONRY - PART 6: DETERMINATION OF TENSILE AND COMPRESSIVE LOAD CAPACITY AND LOAD DISPLACEMENT CHARACTERISTICS OF WALL TIES (SINGLE END TEST)
UNE-EN 772-1:2011 Methods of test for masonry units - Part 1: Determination of compressive strength

EN 998-2:2016 Specification for mortar for masonry - Part 2: Masonry mortar
ISO 12491:1997 Statistical methods for quality control of building materials and components
EN 772-18:2011 Methods of test for masonry units - Part 18: Determination of freeze-thaw resistance of calcium silicate masonry units
EN 772-1:2011+A1:2015 Methods of test for masonry units - Part 1: Determination of compressive strength
EN 1745:2012 Masonry and masonry products - Methods for determining thermal properties
EN 772-21:2011 Methods of test for masonry units - Part 21: Determination of water absorption of clay and calcium silicate masonry units by cold water absorption
ISO 12572:2016 Hygrothermal performance of building materials and products Determination of water vapour transmission properties Cup method
EN 772-16:2011 Methods of test for masonry units - Part 16: Determination of dimensions
EN ISO 12572:2016 Hygrothermal performance of building materials and products - Determination of water vapour transmission properties - Cup method (ISO 12572:2016)
EN 1996-1-1:2005+A1:2012 Eurocode 6 - Design of masonry structures - Part 1-1: General rules for reinforced and unreinforced masonry structures
BS 187:1978 Specification for calcium silicate (sandlime and flintlime) bricks
PD 6697:2010 Recommendations for the design of masonry structures to BS EN 1996-1-1 and BS EN 1996-2
BS EN 772-18:2011 Methods of test for masonry units Determination of freeze-thaw resistance of calcium silicate masonry units
EN 772-13:2000 Methods of test for masonry units - Part 13: Determination of net and gross dry density of masonry units (except for natural stone)
BS 6649:1985 Specification for clay and calcium silicate modular bricks

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, flexible and cost effective.