IEC 60601-2-33:2002/AMD1:2005

Amendment 1 - Medical electrical equipment - Part 2-33: Particular requirements for the safety of magnetic resonance equipment for medical diagnosis

Amendement 1 - Appareils électromédicaux - Partie 2-33: Règles particulières de sécurité relatives aux appareils à résonance magnétique utilisés pour le diagnostic médical

General Information

• Status: Published
• Publication Date: 29-Aug-2005
• ICS: 11.040.55 - Diagnostic equipment
• Technical Committee: SC 62B - Medical imaging equipment, software, and systems
• Drafting Committee: WG 28 - TC 62/SC 62B/WG 28
• Current Stage: DELPUB - Deleted Publication
• Completion Date: 10-Mar-2010

Relations

• Amends: IEC 60601-2-33:2002 - Medical electrical equipment - Part 2-33: Particular requirements for the safety of magnetic resonance equipment for medical diagnosis
• Effective Date: 05-Sep-2023
• Revised: IEC 60601-2-33:2010 - Medical electrical equipment - Part 2-33: Particular requirements for the basic safety and essential performance of magnetic resonance equipment for medical diagnosis
• Effective Date: 05-Sep-2023

Standards Content (Sample)

INTERNATIONAL IEC
STANDARD 60601-2-33
AMENDMENT 1
2005-08
Amendment 1
Medical electrical equipment –
Part 2-33:
Particular requirements for the safety
of magnetic resonance equipment
for medical diagnosis
 IEC 2005 Droits de reproduction réservés  Copyright - all rights reserved
International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland
Telephone: [phone] Telefax: [phone] E-mail: [e-mail] Web: www.iec.ch
PRICE CODE
Commission Electrotechnique Internationale H

International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue

– 2 – 60601-2-33 Amend. 1  IEC:2005(E)

FOREWORD
This amendment has been prepared by subcommittee 62B: Diagnostic imaging equipment, of

IEC technical committee 62: Electrical equipment in medical practice.

The text of this amendment is based on the following documents:

FDIS Report on voting
62B/573/FDIS 62B/586/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
___________
Page 13
6.8.2 INSTRUCTIONS FOR USE
Replace, on page 18, the existing item pp) by the following:
pp) Recommended training
INSTRUCTIONS FOR USE shall recommend that training is needed for physicians and the
OPERATOR to operate the MR EQUIPMENT safely and effectively. This training shall include
emergency procedures, including those for the issues described in this subclause under
− cc) Emergency medical procedures
− ee) CONTROLLED ACCESS AREA
− mm) EMERGENCY FIELD SHUT DOWN UNIT
− nn) Fire precautions
− ss) Emergency actions in the event of a QUENCH.
Add, on page 18, the following new item ss):
* ss) Emergency actions in case of a QUENCH
The INSTRUCTIONS FOR USE shall include instructions on how to identify a QUENCH and how
to act in the event of a QUENCH, especially when the venting system of the
superconducting magnet system fails.

60601-2-33 Amend. 1  IEC:2005(E) – 3 –

Page 19
6.8.3 Technical description
Replace, on page 20, the existing item cc) by the following:

* cc) Safety provisions in the event of a quench

For MR EQUIPMENT equipped with superconducting magnets, the ACCOMPANYING

DOCUMENTS shall
– state the requirements for a venting system for the superconducting magnet which

connects the cryostat of the magnet to the outside atmosphere and which is designed

to withstand a QUENCH and to protect nearby persons in the event of a QUENCH;
– provide guidelines for the construction (dimensions, position, assembly and material to
be applied) of the venting system for the superconducting magnet inside and outside
the examination room;
– recommend a preventive maintenance program, which states that regular checks of the
adequateness of the function of the venting system for the superconducting magnet
are to be made;
– state requirements for the design of the examination room to increase safety of the
patient and other persons inside and outside the examination room in the event of
failure of the venting system during a quench. The suggested design shall address the
issues of reducing pressure build-up, temperature decrease and oxygen depletion
during a quench. A number of acceptable solutions for such provisions, demonstrated
to be effective by simulation or test, shall be listed, so that even when the venting
system of the superconducting magnet fails to work adequately, the chance of a
hazard for the PATIENT or other persons inside as well as outside the examination
room, as caused by PRESSURE build-up, temperatures decrease or oxygen depletion
during the QUENCH, is reduced considerably;
– state the need for the USER to establish an emergency plan for a quench, including a
situation in which the venting system for the superconducting magnet fails to function
adequately;
– state the need for possible extra control measures for the PATIENT ventilation system in
order not to expose the PATIENT to additional helium transported to the PATIENT via the
PATIENT ventilation system. The PATIENT ventilation system should have its inlet
opening in a safe place (such as at a low level in the examination room or directly
connected to the air-conditioning of the examination room), or be connected to a
QUENCH detector, so that the PATIENT ventilation system can be automatically controlled
when a QUENCH occurs and will not transport helium to the PATIENT inside the scanner.
NOTE 1 The venting system for the superconducting magnet is considered to be the cryogenic vent pipe and all
the extra components necessary to safely accommodate a QUENCH.
NOTE 2 Examination room configurations demonstrated by simulation or test that are acceptable include:

− configurations in which the RF door opens outwards or is a sliding RF door;
− configurations in which the RF door opens inwards, if these include extra precautions to prevent PRESSURE
build up. This can be realized by one of the following
• an extra examination room ventilator system, which can be switched on (possibly automatically via an
oxygen monitor in the ceiling of the examination room to detect the escape of helium gas) in the
event of a QUENCH; or
• an opening in the wall or ceiling of the examination room, venting towards an open area; or
• a possibility of opening the observation window in the examination room outward or by sliding; or
• a second independent venting system for the superconducting magnet that remains operational in
case the regular venting system for the superconducting magnet is obstructed; or
• equivalent methods demonstrated to be effective by simulation or test.

– 4 – 60601-2-33 Amend. 1  IEC:2005(E)

Page 45
Annex BB – Guidance and rationale for particular subclauses

Add, on page 57, a rationale for subclause item 6.8.2 ss) as follows:

Concerning 6.8.2 ss)
In addition to the information given in Clause 6.8.2 cc) on emergency medical procedures and

clause 6.8.2 ff) on liquid and gaseous cryogens, this item provides information pertinent to

emergencies present in the event that magnet helium gas escapes from the magnet into the
examination room or other adjacent rooms during a QUENCH. This situation may be present
when the venting system of the superconducting magnet fails either in part or fully during a
magnet QUENCH. In this case, hazards may be present for the personnel involved. The
information provided here will be useful for the OPERATOR in establishing an emergency plan
adapted to local requirements.
While a QUENCH as such is a rare event, the additional failure of a venting system of the
magnet is even more unlikely. Although thousands of MR SYSTEMS are in operation, there
have been only a few reports to date regarding accidents or near accidents involving personal
injuries in relationship to a QUENCH. Nevertheless, the MANUFACTURERS are required to point
out the potential hazard of the combined event and to provide information pertinent to this
type of emergency. Note that the information covers the highly unlikely, yet possibly serious
event of a malfunctioning venting system at the time of a quench of the superconducting
magnet.
What is a QUENCH?
During a QUENCH, the magnet loses its super-conductivity. The magnetic field ramps down in a
matter of seconds – typically lasting approximately 20 seconds. The magnet begins to warm
up. Liquid helium boils off at a rate of 500 to 1 500 l within a few minutes and expands
quickly. The exact boil-off rate amount depends on the fill level as well as the field strength of
the magnet. A 3 T magnet may have a higher boil-off rate than a 1,5 T magnet. One litre of
liquid helium translates into approximately 700 l of gaseous helium. During maximum
conditions this means approximately 1 000 m³ of gas. A manual QUENCH may be initiated by
activating the Emergency field shut down unit. Another source for quenching is when the
helium fill level decreases to a point where the magnet begins to warm up. In rare instances,
a spontaneous QUENCH may be observed that cannot be explained by the presence of obvious
causes.
Hissing or whistling noises caused by the quickly escaping stream of cold helium gas may

accompany a QUENCH. Plumes of white fog sink to the floor mainly from the upper part of the
magnet from the vicinity of the QUENCH line due to condensation of both water vapour and air.
The stream of helium gas diminishes in a matter of minutes. Air near the non-insulated
components of the magnet and the QUENCH line condenses into liquid air and drips to the
floor.
Risks associated with a failing venting system
The purpose of the venting system of the superconducting magnet is to securely exhaust
gaseous helium to the outside. The main element of this system is a conduit that is designed
to transport the escaping helium gas to a safe open area. The possibility of a QUENCH should
be taken into careful consideration during the design of both the magnet and the venting
system of the superconducting magnet. As a result, a QUENCH should be completely harmless
to personnel. Also, neither the magnet nor the MR installations as such should be subject to
damage during a QUENCH.
60601-2-33 Amend. 1  IEC:2005(E) – 5 –

An emergency situation will arise if a quench venting system fails. Helium is lighter than air,

and is non-poisonous and non-flammable. However, since it displaces oxygen, the risk of

suffocation exists. Cryogenic helium escaping into the ambient air leads to white clouds

caused by condensation. These clouds will adversely affect visibility.

Persons may be rendered unconscious by the amount of helium entering their respiratory

system. Depending on the helium concentration present in the air, a few breaths may suffice

to result in unconsciousness.
In addition, escaping helium is extremely cold, possibly causing hypothermia and frostbite.

The latter results in injuries resembling burns (cryogenic burns) after the skin is exposed to

normal temperature levels. Skin contact with cold parts or liquid air may also lead to frostbite.
A variety of failures of the venting system of the superconducting magnet are conceivable. For
instance, the following may occur.
− Small leaks: smaller amounts of helium gas are exhausted to the outside via the heating
and air conditioning system and replaced by fresh air. This is not a critical situation as
long as the heating and air conditioning system functions as required.
These leakages are the result of constructional errors that need to be corrected.
− The venting system of the superconducting magnet fails in part: only part of the helium
gas is exhausted to the outside via the integrated venting system. Larger amounts of
helium are present in the examination room. The heating and air conditioning system
cannot remove the helium due to its volume. Large clouds form, which adversely effects
visibility. Additionally, the PRESSURE in the room increases. Depending on the size of the
leakage, hazardous conditions may be present for the personnel involved.
− Total failure: the venting system of the superconducting magnet fails completely, e.g.
through blockage or breaks in the line. The entire amount of gas is exhausted into the
examination room. If the requirements and recommendations previously mentioned are
not followed, there is an increased potential for loss of life in the case of a complete
cryogen vent failure.
− Up to 1 000 m of gas are blown into the room, which frequently has a volume of less than
100 m .
Add, on page 58, a rationale for subclause item 6.8.3 cc) as follows:
Concerning 6.8.3 cc)
Examination room configuration
A number of examination room features are suggested in the standard. For the examination

room features a clear distinction is made between the helium venting system for the
superconducting magnet needed in case of a QUENCH and the PATIENT ventilation system
needed for daily air refreshment for the PATIENTS. The examination room features try to
maximise the time available to remove a PATIENT from the system in the event of a QUENCH
associated with a failing venting system of the superconducting magnet. These features will
help increase the time available to remove a patient to an average time of a few minutes. In
general the operation of the PATIENT ventilation system should be monitored carefully. Some
PATIENT ventilation systems bring fresh conditioned air from the top of the examination room
to the PATIENT. In the event of a QUENCH associated with a failing venting system of the
superconducting magnet, this is very unfavourable for the PATIENT, and the operation of the
PATIENT ventilation system should be stopped, preferably automatically via the detection of the
QUENCH by a sensor. Also, an automated warning to the OPERATOR can be considered in all
situations.The fitting of an oxygen monitor, wired to audible and visual alarms, in the ceiling of
the examination room to give an early warning of the escape of helium gas is recommended.
When remodelling of the examination room is performed, the integrity of the RF-shielding has
to be tested again.
– 6 – 60601-2-33 Amend. 1  IEC:2005(E)

Door of the examination room opens inwards – constructional safety measures

The most unfavourable situation for the examination room is when the door of the examination

room opens inwards. In this situation, slight overpressure due to helium gas leakage may

make opening of the door extremely difficult. Depending on the ventilation system for the

room, overpressure may be present for a considerable length of time. Installation of a
provision in the examination room to allow air breathing for persons present in the

examination room during the QUENCH in this situation may help to increase the time available

to allow for pressure equalization in the room.

To address this situation the f
...

IEC 60601-2-33
Edition 2.0 2005-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Medical electrical equipment –
Part 2-33: Particular requirements for the safety of magnetic resonance
equipment for medical diagnosis

Appareils électromédicaux –
Partie 2-33: Règles particulières de sécurité relatives aux appareils à résonance
magnétique utilisés pour le diagnostic médical

IEC 60601-2-33:2002/A1:2005
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IEC 60601-2-33
Edition 2.0 2005-08
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
AMENDMENT 1
AMENDEMENT 1
Medical electrical equipment –
Part 2-33: Particular requirements for the safety of magnetic resonance
equipment for medical diagnosis

Appareils électromédicaux –
Partie 2-33: Règles particulières de sécurité relatives aux appareils à résonance
magnétique utilisés pour le diagnostic médical

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
J
CODE PRIX
ICS 11.040.55 ISBN 2-8318-0000-0
– 2 – 60601-2-33 Amend.1 © CEI:2005

AVANT-PROPOS
Cet amendement a été établi par le sous-comité 62B: Appareils d'imagerie de diagnostic, du

comité d’études 62 de la CEI: Equipements électriques dans la pratique médicale.

Cette version bilingue, publiée en 2006-02, correspond à la version anglaise.

Le texte anglais de cet amendement est issu des documents 62B/573/FDIS et 62B/586/RVD.

Le rapport de vote 62B/586/RVD donne toute information sur le vote ayant abouti à

l'approbation de cet amendement.

La version française de cet amendement n’a pas été soumise au vote.
Le comité a décidé que le contenu du présent amendement et de la publication de base ne
sera pas modifié avant la date de maintenance indiquée sur le site web de la CEI, sous
"http://webstore.iec.ch", dans les données relatives à cette publication spécifique. A cette
date, la publication sera
• reconduite,
• supprimée,
• remplacée par une édition révisée, ou
• amendée.
___________
Page 13
NSTRUCTIONS D’UTILISATION
6.8.2 I
Remplacer, page 18, le point pp) existant par le point suivant:
pp) Formation recommandée
Les INSTRUCTIONS D’UTILISATION doivent indiquer dans les recommandations que la
formation est nécessaire aux médecins et à l’OPERATEUR pour faire fonctionner l’APPAREIL
A RM en toute sécurité et efficacement. Cette formation doit comprendre des procédures
d’urgence, y compris celles pour les problèmes décrits dans le présent article aux points
suivants:
− cc) Procédures d'urgence médicale
− ee) ZONE A ACCES CONTROLE
− mm) UNITE DE COUPURE D'URGENCE DU CHAMP
− nn) Mesures contre le feu
− ss) Actions d’urgence en cas de QUENCH.
Ajouter, à la page 18, le nouveau point ss) suivant:
* ss) Actions d’urgence en cas de QUENCH
Les INSTRUCTIONS D’UTILISATION doivent inclure des instructions sur la façon d’identifier un
QUENCH et sur la façon d’agir dans le cas d'un QUENCH, en particulier lorsque le système
de ventilation du système d’aimant supraconducteur est défaillant.

60601-2-33 Amend. 1 © IEC:2005 – 3 –

FOREWORD
This amendment has been prepared by subcommittee 62B: Diagnostic imaging equipment, of

IEC technical committee 62: Electrical equipment in medical practice.

This bilingual version, published in 2006-02, corresponds to the English version.

The text of this amendment is based on the following documents:

FDIS Report on voting
62B/573/FDIS 62B/586/RVD
Full information on the voting for the approval of this amendment can be found in the report
on voting indicated in the above table.
The French version of this amendment has not been voted upon.
The committee has decided that the contents of this amendment and the base publication will
remain unchanged until the maintenance result date indicated on the IEC web site under
"http://webstore.iec.ch" in the data related to the specific publication. At this date, the
publication will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
___________
Page 13
6.8.2 INSTRUCTIONS FOR USE
Replace, on page 18, the existing item pp) by the following:
pp) Recommended training
INSTRUCTIONS FOR USE shall recommend that training is needed for physicians and the

OPERATOR to operate the MR EQUIPMENT safely and effectively. This training shall include
emergency procedures, including those for the issues described in this subclause under
− cc) Emergency medical procedures
− ee) CONTROLLED ACCESS AREA
− mm) EMERGENCY FIELD SHUT DOWN UNIT
− nn) Fire precautions
− ss) Emergency actions in the event of a QUENCH.
Add, on page 18, the following new item ss):
* ss) Emergency actions in case of a QUENCH
The INSTRUCTIONS FOR USE shall include instructions on how to identify a QUENCH and how
to act in the event of a QUENCH, especially when the venting system of the
superconducting magnet system fails.

– 4 – 60601-2-33 Amend.1 © CEI:2005

Page 19
6.8.3 Description technique
Remplacer, page 20, le point cc) existant par le point suivant:

* cc) Dispositions de sécurité en cas de QUENCH

Pour les APPAREILS A RM équipés d'aimants supraconducteurs, les DOCUMENTS D’ACCOMPA-

GNEMENT doivent
– stipuler des exigences pour un système de ventilation pour l’aimant supraconducteur

qui connecte le cryostat de l’aimant à l’atmosphère extérieure et qui est conçu pour

résister à un QUENCH et pour protéger les personnes proches dans le cas d'un QUENCH;
– fournir des lignes directrices pour la construction (dimensions, position, assemblage et
matériau à appliquer) du système de ventilation pour l’aimant supraconducteur à
l’intérieur et à l’extérieur de la salle d’examen;
– recommander un programme d’entretien préventif, qui établit que des vérifications
régulières de l’adéquation de la fonction du système de ventilation pour l’aimant
supraconducteur doivent être effectuées;
– établir des exigences pour la conception de la salle d’examen, afin d’augmenter la
sécurité du patient et des autres personnes à l'intérieur et à l'extérieur de la salle
d'examen en cas de défaillance du système de ventilation au cours d’un QUENCH. La
conception recommandée doit traiter des questions soulevées par la réduction de la
formation de pression, par la baisse de température ou par l'appauvrissement en
oxygène au cours d'un QUENCH. Un certain nombre de solutions acceptables pour de
telles dispositions, démontrées comme étant efficaces par simulation ou par des
essais, doivent être énumérées, de telle sorte que, même lorsque le système de
ventilation de l’aimant supraconducteur ne fonctionne pas correctement, la probabilité
de risque pour le PATIENT ou pour toute autre personne se trouvant à l’intérieur ou à
l’extérieur de la salle d’examen, pouvant être induit par une formation de PRESSION,
une baisse de température ou un appauvrissement en oxygène au cours du QUENCH,
soit réduite de façon considérable;
– indiquer la nécessité pour l’UTILISATEUR d’établir un plan d’urgence en cas de QUENCH,
y compris la situation pour laquelle le système de ventilation de l’aimant
supraconducteur ne fonctionne pas correctement;
– indiquer la nécessité de mesures de contrôle supplémentaires éventuelles pour le
système de ventilation du PATIENT, afin de ne pas exposer le PATIENT à une quantité
supplémentaire d’hélium, acheminé vers le PATIENT par le système de ventilation du
PATIENT. Il convient que l’ouverture d’entrée du système de ventilation du PATIENT soit
située dans un lieu sûr (par exemple à un niveau bas dans la salle d’examen ou
directement connectée à la climatisation de la salle d’examen), ou qu’elle soit
connectée à un détecteur de QUENCH, de telle sorte que le système de ventilation du

PATIENT puisse être commandé automatiquement lorsqu’un QUENCH se produit et qu’il
ne transporte pas d’hélium vers le PATIENT à l’intérieur du tomodensitomètre.
NOTE 1 Le système de ventilation pour l’aimant supraconducteur est considéré comme étant le conduit de
ventilation cryogénique et tous les composants supplémentaires nécessaires pour s’adapter en toute sécurité à un
QUENCH.
NOTE 2 Les configurations de la salle d’examen, démontrées par simulation ou par des essais, qui sont
acceptables comprennent:
− des configurations dans lesquelles la porte RF s’ouvre vers l’extérieur ou est une porte coulissante;
− des configurations dans lesquelles la porte RF s’ouvre vers l’intérieur, si celles-ci comprennent des
précautions supplémentaires afin d’empêcher une formation de PRESSION. Ceci peut être réalisé dans l'un ou
l'autre des cas suivants:
• un système de ventilation supplémentaire dans la salle d’examen, qui peut être mis en marche
(éventuellement de manière automatique par un moniteur d’oxygène situé dans le plafond de la salle
d'examen pour détecter l'évacuation d'hélium gazeux) dans le cas d'un QUENCH; ou
• une ouverture dans les murs ou le plafond de la salle d’examen, ventilant vers un espace libre; ou

60601-2-33 Amend. 1 © IEC:2005 – 5 –

Page 19
6.8.3 Technical description
Replace, on page 20, the existing item cc) by the following:

* cc) Safety provisions in the event of a quench

For MR EQUIPMENT equipped with superconducting magnets, the ACCOMPANYING

DOCUMENTS shall
– state the requirements for a venting system for the superconducting magnet which

connects the cryostat of the magnet to the outside atmosphere and which is designed

to withstand a QUENCH and to protect nearby persons in the event of a QUENCH;
– provide guidelines for the construction (dimensions, position, assembly and material to
be applied) of the venting system for the superconducting magnet inside and outside
the examination room;
– recommend a preventive maintenance program, which states that regular checks of the
adequateness of the function of the venting system for the superconducting magnet
are to be made;
– state requirements
...