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i-Size regulations

i-Size regulations

The future is here:  the new i-Size rating

Until now, for a child car seat to be used in Spain (and the EU) it had to be approved according to all the tests included within the Child Safety Standard ECE R44/04

In a few months time, the seats can also approved according to the new Standard: ECE R129, known as i-size.

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The new rating is designed to simplify the whole process of choosing a child car seat, making them more universal and so easier to use.

The new regulation is known simply as "super ISOFIX".Using the letter "i" from the word ISOFIX to give is the term i-Size. 

The principal innovations included in the new ECE 129 legislation are:

  • It dispenses with the classifications by groups 0/0+/I/II/III (and the weight of the child suitable to each group) so that each seat will be labeled with the size (height) and maximum weight of the child that can use it, in a similar way to choosing childrens clothes sizes.
  • Included is a new side impact test, making the seat much safer in this type of accident.
  • It makes the use of backward facing seats up to at least 15 months of age mandatory.This will encourage the use of backward facing seats which is a much safer alternative than forward facing seats.
  • It defines the maximum dimensions of the child seat and the minimum dimensions of the car seat, so that any child seat approved as i-Size can be used can be used on any i-Size car seat.So unlike with the present regulations, ECE R44/04, included in which there are universal and semi-universal seats suitable for specific vehicles, with  ECER129, all seats are universal and can be used an any vehicle equipped with i-Size seats.
  • The testing is carried out using dummies or manequins that incorporate new, more advanced, injury criteria. How do I recognize and i-Size seat?

The new seat certification label for ECE R129 or "i-Size" will display the following logo with the letter "i".


The child car seats "i-Size" approved under the new regulation ECE R129, will also display the following logo with the letter "i":


Any vehicle seat that complies with the i-Size dimensions is guaranteed to allow the installation of any i-Size child seat that carries the "i-Size" logo

First of all, the new regulations adds a new side impact crash test to verify the protection given by the seat in this type of accident.Secondly, the ECE R129 regulations guarantee that any i-Size child seat can be installed in any i-Size vehicle, which is an improvement on the present system whereby certain ISOFIX seats can only be installed in specific vehicles.

In short, the principal advantages of "i-Size" seats are:

  1. Better protection for the head and neck in head-on collisions as it encourages the use of backward facing seats, which are 5 times safer than forward facing seats, at least up to 15 months of age

  2. Better protection in lateral collisions.

  3. less danger of incorrect installation.

In Spain it is now legal to buy and use i-Size seats.*

*OFFICIAL STATE BULLETIN, no. 158 of Monday 30th June 2014 section I page.49879 published the order IET/1105/2014 of THE MINISTRY OF INDUSTRY, ENERGY AND TOURISM, of 26th of June, in which the annexes I and II of the Royal Decree 2028/1086, of the 6th of June, regarding the application of the EEC directives relative to the the approval of vehicle types, trailers, tractor and trailers, motorbikes, mopeds and agricultural vehicles or any parts of said vehicles and indicating that the ECE R129 is optional. 

No, for the time being, seats approved under the ECE R44/004 standard can continue be used without problems.

The R-129 and R-44 standards are both in force and child seats approved under both pieces of legislation can be used. 

Each child car seat manufacturer chooses to approve their seats in Europe according to either of the technical standards.

However, there is an increasing trend for R-129 to replace R-44 which will eventually cease to exist.

Not for the time being, no.

The first stage of the new EC R-129 legislation,  ending with i-Size, was passed in November 2012 and entered into force in July 2013. This stage only covers integrated seats, i.e. those which have a harness to secure the child in the seat and must be secured with the ISOFIX system.

The second stage was passed on 22 June 2017 and relates to non-integrated restraint devices, namely those devices which are secured with the car's seat belt, and for children over 100 cm tall. This second stage advocates for the use of booster seats with backrests. 

The third stage is still under development. This stage is dealing with the amendments needed in order to update the ECE R44 standard for non-ISOFIX child seats (those which are secured to the vehicle with a seat belt) and the ECE R14 and ECE R16 standards (on seat belts and their anchorage to the vehicle) so that non-ISOFIX child car seats can also comply with the new criteria included in stages 1 and 2. 

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