ISO/TR 11071-2:2006

TECHNICAL ISO/TR
REPORT 11071-2
Second edition
2006-04-15
Comparison of worldwide lift safety
standards —
Part 2:
Hydraulic lifts (elevators)
Comparaison des normes mondiales de sécurité des ascenseurs —
Partie 2: Ascenseurs hydrauliques

Reference number
©
ISO 2006
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ii © ISO 2006 – All rights reserved

Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Terminology . 1
3 Basis for lift safety standards development (basic assumptions) . 5
4 Approach to design safety for hydraulic components . 13
5 Driving Machines and jacks (plungers and cylinders). 33
6 Valves, Piping and Fittings . 44
7 Ropes and chains . 59
8 Capacity and loading. 65
9 Spaces and clearances . 75
10 Protection against free-fall, excessive speed and creeping . 78
11 Electrical devices. 83
Annex A (informative) Tabulations . 88
Annex B (informative) References. 113
Annex C (informative) CEN/TC10/WG1 N99. 115

Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
technical committees. Each member body interested in a subject for which a technical committee has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
In exceptional circumstances, when a technical committee has collected data of a different kind from that
which is normally published as an International Standard (“state of the art”, for example), it may decide by a
simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely
informative in nature and does not have to be reviewed until the data it provides are considered to be no
longer valid or useful.
ISO/TR 11071-2 was prepared by Technical Committee ISO/TC 178, Lifts, escalators and moving walks.
This second edition cancels and replaces the first edition (ISO/TR 11071-2:1996), and amendment 1
(ISO/TR 11071-2:1996/Amd. 1:1999), which have been technically revised.
ISO/TR 11071 consists of the following parts, under the general title Comparison of worldwide lift safety
standards:
⎯ Part 1: Electric lifts (elevators)
⎯ Part 2: Hydraulic lifts (elevators)
iv © ISO 2006 – All rights reserved

Introduction
Introduction to 1996 edition
At the 1981 plenary meeting of ISO/TC 178, work was started on a comparison of CEN standard EN 81/1 with
the American, Canadian, and USSR lift safety standards. In 1983, Working Group 4 was officially formed to
carry out the task of preparing cross reference between the relevant sections of these standards and to
analyze the differences on selected subjects. The goal at that time was to prepare a technical report which
would provide reference information to assist national committees when reviewing and revising individual
standards which may initiate a gradual convergence of the technical requirements. In 1984, the study was
expanded to include the Council for Mutual Economic Assistance (CMEA) safety standard. That report,
ISO/TR 11071-1, Comparison of worldwide lift safety standards — Part 1: Electric lifts (elevators), was
published 1990-12-01.
In 1989, the charge to WG 4 was expanded to include hydraulic lifts. Since there was no standard for
hydraulic lifts in the Russian Federation, and the CMEA standard was being phased out of use, this Part 2 of
the comparison is generally limited to the ASME, CEN, and CSA standards. The Japan Elevator Association
was invited to add their standards to this comparison, however, no response to this request was received.
This report is intended to aid standards writers in developing their safety requirements, and to help standard
users understand the basis for the requirements as they are applied throughout the world.
This report is not intended to replace existing safety standards. Conclusions are arrived at in some cases, but
only where there is unanimity amongst the various experts. In other cases, the reasons for the divergent views
are expressed.
This report must be read in conjunction with the various safety standards, as it was often necessary to
summarize the requirements for the sake of clarifying the comparisons. Further, the information contained in
this report does not necessarily represent the opinions of the standards writing organizations responsible for
the development of the safety standards which are being compared, and they should be consulted regarding
interpretations of their requirements (see Annex B).
Introduction to this edition
After the original publication (1996) of this technical report, including American, Canadian and European data
and thereto Supplement 1 (1999-08-01), which added Australian and Japanese data, has been revised or
amended. The recommendations in the form of “agreed upon points” stated in the first edition have also
affected the revisions of the national standards.
The original report and amendment have been widely used by lift industry and standards writing organizations,
including the ISO Technical Committee 178. Users have expressed need for an updated and consolidated
version of the document, in particular the comparison tabulations. With the Resolution 208/2002, the
ISO/TC 178 requested WG4 to consolidate original publications, including Supplements and “to update
comparison tables in ISO/TR 11071 with data from the most recently published standards for lifts and to
republish both documents, Part 1 and Part 2 with updated tables and with minimum changes to the narrative
sections”.
The narrative sections of the original publication, in particular assumptions, historical backgrounds,
observations and suggestions as well as the points agreed upon were the result of extensive work of the
ISO/TC 178 Working group 4. ISO/TC 178 is currently working on a new series of ISO documents under the
general title Safety requirements for lifts (elevators). In that process the updated comparison tables are being
used as reference. Extensive work on complete re-write of the narrative sections was not deemed necessary.
However, republication of the text with only minor editorial changes would help readers to understand the
background to the safety concerns being addressed in the current national standards. However, because of
recent (2000) harmonization of ASME and CSA Codes, it was necessary to replace the quoted rule numbers
with those in the current Codes In most sentences the ASME and CSA. I some other cases quoted references
are updated in a NOTE following the narrative section or sentence.
All quoted requirement referenced in all tables (CEN, ASME/CSA, Japan and SA) are up to date.

vi © ISO 2006 – All rights reserved

TECHNICAL REPORT ISO/TR 11071-2:2006(E)

Comparison of worldwide lift safety standards —
Part 2:
Hydraulic lifts (elevators)
1 Scope
This Technical Report consists of a comparison of the requirements of selected topics as covered by the
following worldwide safety standards (excluding regional or national deviations):
a) CEN European Standard EN 81-2:1998, Safety rules for the construction and installation of lifts — Part 2:
Hydraulic lifts;
b) ASME A17.1:2004, Safety Code for Elevators and Escalators and CSA B44:2004, Safety Code for
Elevators;
c) Japan - Building Standard Law of Japan (BSLJ);
d) Standards Australia:
⎯ AS 1735-1:2003, Lifts, Escalators and Moving Walks — Part 1: General Requirements;
⎯ AS 1735-3:2002, Lifts, Escalators and Moving Walks — Part 3: Passenger and Goods Lifts —
Electro-hydraulic.
This Technical Report applies to hydraulic lifts only, both of the direct and indirect acting type.
It should be noted that, in addition to the above listed standards, lifts must conform to the requirements of
other standards (for example, standards covering mechanical, structural, and electrical equipment; building
codes, and environmental regulations). Some of the standards will be referred to in this Technical Report.
2 Terminology
2.1 Lifts and elevators
2.1.1 The CEN term lift corresponds to the ASME and CSA term elevator. These terms are used
inter-changeably in this report.
2.1.2 For the purposes of this report, unless otherwise specified, the terms passenger lift and freight lift
correspond to the following terms used in other Standards:

*
Term used in this
Correspond to terms used in the following standards
report
CEN ASME and CSA
Passenger lift Lift except goods passenger lift Passenger elevator & freight elevator
permitted to carry passengers
**
Freight lift Freight elevator
Goods passenger lift
* See the definitions in the applicable Standards.
**
This term is used only to enable comparisons to be made later in this report. It does not indicate recognition of the term “freight lift”
by CEN.
2.2 Hydraulic terminology
2.2.1 Difference
There are some notable differences in the standards respecting hydraulic lift terminology as shown in the
Table 1, Column A and B.
2.2.2 Agreed-upon points, re: hydraulic terminology
The differences should be eliminated or minimized through proposed changes to ASME and CSA Standards,
as shown in Table 1, Column D.
If approved by ASME and CSA Committees, the proposed changes would eliminate major differences
between CEN and North American Standards.
Column C gives the description of the equipment that a term (listed in Column A, B, or D) embraces.
In addition to “hydraulic machine”, ASME and CSA propose to introduce the term “hydraulic driving machines”
hydraulic driving machines”. The terms are needed to differentiate between “electric” and “hydraulic” driving
machines all covered in one ASME and CSA Standard. This is not necessarily applicable to CEN, as the
electric and hydraulic lifts are covered by two separate standards.
2 © ISO 2006 – All rights reserved

2.2.3 Terminology in this report
In this report, the CEN terminology will be used, with the ASME and CSA terms in brackets if different.
Table 1 — Hydraulic Terminology
Column A Column B Column C Column D
CEN ASME & CSA Description Agreed upon points:
Current ASME & CSA proposed
changes
Direct acting Direct plunger — Direct acting hydraulic
a
elevator
hydraulic elevator
lift
Indirect acting Roped hydraulic — No change
Elevator
lift
b
Machine — Pump, motor, valves Hydraulic Machine
c
Jack Driving machine Cylinder and ram Hydraulic jack
Ram Plunger or piston — Plunger (ram) or piston
Base Head/bottom Cylinder end cap No change
(Includes plunger end
cap as well)
Valves:
Non-return Check — No change
Pressure relief Pump relief — No change
Direction Control — No change
Rupture ASME-Safety CSA-Rupture — No change
NOTE ASME and CSA adopted terms:
a
“direct-acting”.
b
“hydraulic machine".
c
“hydraulic jack”.
2.3 Working pressure vs full load pressure
ASME and CSA use working pressure (WP), which is defined as the pressure at the hydraulic driving machine
when lifting the car and its rated load at rated speed, or with class C2 loading, when leveling up with maximum
static load.
CEN defines full load pressure (FLP) as the static pressure exerted at the piping directly connected to the jack,
the car with the rated load being at rest at the highest landing level.
CEN Annex K, clause K.1.1 recognizes that friction losses as a result of fluid flow are on the order of 15 %;
thus a factor of 1,15 is included in their factor of safety determination.
NOTE CEN reference to “Clause 12, NOTE 1” in this clause and through the 1996 edition of this document has been
replaced with reference to “Annex K, Clause K1.1” in this edition.
Thus, ASME WP = 1,15 x (CEN FLP).
2.4 Other terms
Additional terminology, where there is a difference between the CEN and the ASME and CSA standards, is
shown in Table 2:
NOTE Since ASME and CSA are now harmonized they will be shown through this edition in a column under title
“ASME and CSA” or “ASME/CSA”.
Table 2 — Terminology
CEN ASME and CSA
Docking operation Truck zone operation
Electric safety device Electrical protective device
Fixings Fastenings
Landing door Hoistway door
Mains Main power supply
Reeving ratio Roping ratio
Instantaneous safety gear Type A safeties (instantaneous safeties)
Progressive safety gear Type B safeties (progressive safeties)
Pulley Sheave
Safety gear Safeties
Well Hoistway
2.5 Abbreviations
The following abbreviations are used in this report:
FOS = Factor of safety or safety factor.
YP = Yield point.
WP = Working pressure.
UTS = Ultimate tensile strength.
FLP = Full load pressure.
NOTE See also list of abbreviations in item 4.1.2.
4 © ISO 2006 – All rights reserved

3 Basis for lift safety standards development (basic assumptions)
3.1 Historical background
3.1.1 All lift safety standards assume certain things as being true, without proving them as such, and
stipulate safety rules that are based on these assumptions.
3.1.2 No standard, however, clearly spells out the assumptions used. The CEN committee analyzed its
standard and summarized in the document CEN/TC10/WG1 N99 (see Annex C) the assumptions that, in the
opinion of the committee, were used in the CEN standard.
3.1.3 The CEN assumptions were compared with assumptions implicitly built into other safety standards. It
has been indicated that:
a) some assumptions apparently used in the CEN standard were not listed in the document referred to in
CEN/TC10/WG1 N99;
b) some assumptions used in other standards differ from those in CEN/TC10/WG1 N99.
3.1.4 Using CEN/TC10/WG1 N99 as a model, the following list of assumptions (see 3.3 through 3.9 in this
report) has been developed, which could be used as a basis for future work on safety standards.
The CEN assumptions 5 (related to car speed) and 7 (related to restrictors) as listed in Annex C have not
been considered for adoption in this report, since they are deemed to be design parameters.
Further, CEN assumption 2 is adopted in this report as assumption 1 and CEN assumption 6 as assumption
3(c) in order to be consistent with Part 1 of this report.
In summary, CEN assumptions 1, 3, 4, 8, 9, and 10 correspond to assumptions 1, 2, 3, 4, 5, and 6 in this
report. Assumption 7 is not covered in the CEN document.
3.2 General
3.2.1 Listed in 3.3 through 3.9 (except as noted) are those things specific to lifts that are assumed as true,
although not yet proven or demonstrated as such, including:
a) functioning and reliability of lift components;
b) human behaviour and endurance; and
c) acceptable level of safety and safety margins.
3.2.2 Where the probability of an occurrence is considered highly unlikely, it is considered as not happening.
3.2.3 Where an occurrence proves that an assumption is false, it does not necessarily prove that all other
assumptions are false.
3.2.4 The assumptions should be subject to periodic review by standards writing organizations to ensure
their continuing validity – considering accident statistics, as well as such things as changes in technologies,
public expectations (e.g. product liability), and human behaviour.
3.3 Assumption 1 — safe operation assured to 125 % of rated load
Safe operation of lifts is assured for loads ranging from 0 to 100 % of the rated load. In addition, in the case of
passenger lifts (see 2.1.2), safe operation is also assured for an overload of 25 %; however, it is not
necessary to be able to raise this overload nor to achieve normal operation (rated load performance).
3.3.1 Rationale for Assumption 1
3.3.1.1 All safety standards limit the car area in relation to its rated capacity (load and/or number of
persons) in order to minimize the probability of inadvertent overloading. However, it is recognized that the
possibility of an overloading of up to 25 % still exists on passenger lifts. To eliminate any hazard for
passengers, safe operation must be assured, but not necessarily normal operation.
3.3.1.2 In the case of freight lifts, no overloading is anticipated. It is assumed that designated attendants
and freight handlers will adhere to instructions posted in cars and will not overload them.
3.3.2 Assumption 1 as applied in current standards
3.3.2.1 Currently CEN does not specifically require a 25 % overload safety margin; however, the design
requirements provide for that level of safety.
ASME and CSA requirements 3.16 and 2.16.8 specifically require that safety be assured on passenger lifts in
the case of 25 % overload.
3.3.2.2 With exceptions given in 3.3.2.5, the ratio of the rated load to the car platform area for passenger
lifts is equal (± 5 %) in all standards for the range of 320 to 4 000 kg, and in that respect, universality of the
assumption #1 is achieved.
However, the assumed average weight of a passenger differs: 75 kg (CEN) and 72,5 kg (ASME and CSA).
3.3.2.3 Furthermore, the rated load to car platform area ratio is different for freight lifts.
CEN (non-commercial vehicle with instructed users) 200 kg/m
ASME/CSA (general freight Class A) 244/240 kg/m
(motor vehicle Class B) 146/145 kg/m
(industrial truck Class C) 244/240 kg/m
3.3.2.4 The CEN standard contains two tables showing the ratio between the rated load and the
maximum available car area (for passenger lifts), see Table 3.
The CEN Table “1.1” corresponding to the requirements for electric lifts is based on the rationale explained in
3.3.1.1 and was taken into consideration when formulating the statement in 3.3.2.2.
3.3.2.5 The CEN Table “1.1 A”, acceptable for Goods passengers lifts, is based on the rationale that
where there is a low probability of the car being overloaded with persons, the available area of a hydraulic lift
may be increased up to therein specified maximum, provided that additional safety measures are taken to
ensure the safe interruption in the lift operation. Such measures include:
a) a pressure switch to prevent a start for a normal journey when the pressure exceeds the full load
pressure by more than 20 %;
b) the design of the car, car sling, car-ram connection, suspension means, car safety gear, rupture valve,
clamping or pawl device, guide rails, and buffers must be based on a load resulting from CEN Table “1.1”;
c) the design pressure of the jack and the piping shall not be exceeded by more than 1,4.
Starting point for CEN Table “1.1A” was the comparison of safety factors of driving systems on electric traction
lifts versus hydraulic lifts. On hydraulic lifts the safety factor for the car suspension means and supporting
structure is at least 3 times higher than that of the traction driving systems, when friction between the
suspension ropes and the grooves of the drive sheave is taken into account. Consequently, the safety risk of
unintended car movement downwards due to the overloading on hydraulic lifts is significantly lower than on
electric traction lifts.
6 © ISO 2006 – All rights reserved

Furthermore, assuming that the car weight is equal to the rated load, in that case an overload of x % on the
electric traction lift would correspond to only x/2 % overload for the hydraulic system.
NOTE This is true for machine power only; not for e.g. safety gear operation, guide rails dimensioning, etc.
For car areas up to 5 m , the required rated load in CEN Table “1.1 A” for a hydraulic lift may be 1,6 times less
than the rated load according to CEN Table 1.1.
NOTE 1.6 is an ISO-standard number R5. This is important in view of the rated loads according to ISO 4190-1 1999,
Lift (US: Elevator) installation — art 1: Class I, II, III and VI lifts, e.g. a Goods passengers lift with 5 m available car area
requires 2 500 kg rated load in the case of an electric lift, and 1 600 kg in the case of a hydraulic lift. For car areas bigger
than 5 m there is no mathematical background.
See Table 3 for an abbreviated comparison of the CEN Tables.
Table 3 — CEN Tables
Rated Load Maximum Car Area Increase in Car Area
"1.1 A" over "1.1"
CEN Table 1.1 CEN Table 1.1 A
for Goods passengers lifts
2 2
kg m m %
400 1,17 1,68 44
800 2,00 2,96 48
1 200 2,80 4,08 46
1 600 3,56 5,04 42
over 1 600, add N/A 0,40/100 kg N/A
2 000 4,20 6,64 58
2 500 5,00 8,84 73
over 2 500, add 0,16/100 kg 0,4/100 kg 250
3.3.2.6 Lift components that are normally designed to withstand, without permanent damage, overloads
greater than 25 % (such as ropes, guides, sheaves, buffers, disconnect switches) are not considered in this
comparison.
NOTE 3.3.2.6 CEN Assumption 2 (see Annex C) is not a new assumption, but rather one of the methods as to how
Assumption 1 is applied in the CEN standard.
3.4 Assumption 2 - failure of electric safety devices
The possibility of a failure of an electric safety device complying with the requirement(s) of a lift safety
standard is not taken into consideration.
Since national safety rules for lifts may be based on different assumptions (some are listed below),
universality of Assumption 2 may be questioned.
3.4.1 Rationale for Assumption 2
Reliability and safety performance of lift components designated as electric safety devices is assured if
designed in accordance with rules contained in a given lift safety standard. However, the design rules may be
based on different assumptions.
3.4.2 Assumption 2 as applied in current standards
Most methods of assuring performance reliability of electric safety devices are similar in present standards.
There are, however, differences and inconsistencies, as detailed in section 11.
Section 11.1.3 deals in particular with discrepancies in assumptions implied in requirements for design of
electric safety devices.
3.5 Assumption 3 - failure of mechanical devices
a) With the exception of items listed below, a mechanical device built and maintained according to good
practice and the requirements of a standard comprising safety rules for lifts is assumed not to deteriorate
to the point of creating hazards before the failure is detected.
NOTE National practices and safety rules may be different, such as safety factors. See sections 4.1.3 and 4.2.1 of
this report;
b) the possibility of the following mechanical failures shall be taken into consideration:
1) rupture of car suspension means;
2) rupture and slackening of any connecting means such as safety related auxiliary ropes, chains and
belts where the safety of normal lift operation or the operation of a safety related standby component
is dependent on such connections;
NOTE Since 2000, overspeed valve is required by ASME and CSA when flexible hoses are used and
when elevator is located in seismic risk zones 2 or greater;
3) small leakage in the hydraulic system (jack included);
c) the possibility of a car or counterweight striking a buffer at a speed higher than the buffer's rating is not
taken into consideration;
d) the possibility of a simultaneous failure of a mechanical device listed above and another mechanical
device provided to ensure safe operation of a lift, should the first failure occur, is not taken into
consideration.
NOTE 1 The Working Group could not agree upon adopting the CEN Assumption 4.3 (see Annex C) requiring that “the
possibility of rupture in the hydraulic system (jack excluded) shall be taken into consideration”;
NOTE 2 Presently, this assumption is implemented only in CEN by requiring a rupture valve or similar devices, while
CSA assumes the rupture of flexible hoses only and in that case only, the rupture valve is required. In ASME, the
overspeed valve (safety valve) is only required in seismic risk zones 2 or greater.
NOTE 3 The CEN rupture valve protects only in the case of rupture of piping, not the cylinder. The USA's experience
indicates that most problems arise from the rupture of cylinders rather than piping;
NOTE 4 Refer to section 10 and table 12 in this Report for detailed comparison of requirements for free fall and
excessive speed protection.
3.5.1 Rationale for Assumption 3
3.5.1.1 Although recent accident records do not support the assumption in 3.5 (b)(1), most safety
standards (including those studied in the preparation of this report) still assume that the risk of suspension
means failure, in particular wire ropes and chains, exists.
3.5.1.2 With the assumption in 3.5 (b)(2) it is recognized that the listed components could deteriorate to
the point of creating a direct or potential hazard (by making a safety related standby component inoperative)
before the deterioration is detected.
8 © ISO 2006 – All rights reserved

3.5.2 Assumption 3 as applied in current standards
3.5.2.1 CEN (9.5.1) clearly assumes failure of suspension means, while ASME and CSA requirement
3.17 imply that safety gear must be able tostop, or at least slow down, a free falling car.
3.5.2.2 Standards differ significantly in regard to the rupture or slackening of connecting means. Only
CEN seems to be consistent in adopting this assumption. Some standards are inconsistent, e.g. ASME and
CSA requirement 2.25.2.3.2 anticipate failure of tapes, chains or ropes operating normal terminal stopping
devices, but they do not anticipate failure of an overspeed governor rope. Only CEN (9.10.2.10.3) assumes
the possibility of governor rope failure.
3.5.2.3 All standards have adopted the assumption that the possibility of a car or counterweight striking
buffers at a speed higher than the buffer's rating is not taken into consideration.
3.5.2.4 All standards have adopted the assumption that the possibility of a simultaneous failure of a
mechanical device mentioned in Assumption 3 and another mechanical device provided to ensure safe
operation of a lift, should the first failure occur, is not taken into consideration.
3.5.2.5 All standards require an anti-creep system based on assumption 3.5 (b)(3).
3.6 Assumption 4 - imprudent act by users
A user may in certain cases make one imprudent act, intentionally made to circumvent the safety function of a
lift component without using special tools. However, it is assumed that:
a) two imprudent acts by users will not take place simultaneously; and
b) an imprudent user's act and the failure of the backup component designed to prevent the safety hazard
resulting from such imprudent acts will not take place simultaneously (e.g. a user manipulating an
interlock and a safety circuit failure).
3.6.1 Assumption 4 as applied in current standards
All three standards are based on this assumption.
3.7 Assumption 5 - neutralization of safety devices during servicing
If a safety device, inaccessible to users, is deliberately neutralized in the course of servicing work, the safe
operation of the lift is no longer assured.
3.7.1 Rationale for Assumption 5
If a mechanic, while servicing a lift, neutralizes or circumvents a safety device (e.g. bypassing door interlocks
using a jumper cable or readjusting overspeed governor) safe lift operation cannot be assured.
While it is assumed that lifts will be designed to facilitate ease of servicing work and that service mechanics
will be equipped with adequate instructions, tools and expertise to safely service lifts, it is recognized that "fail-
safe" service work can never be assured solely by the design of a lift.
3.7.2 Assumption 5 as applied in existing standards
3.7.2.1 All three standards are based on this assumption.
3.7.2.2 The standards, however, differ in requirements for the “tools” that must be provided by the design
of a lift in order to facilitate ease and safety of servicing work. All standards require stop switches on the car
roof, in the hoistway pit and pulley room, and also means for inspection operation from the car top. The
standards differ in the following:
a) CEN (7.7.3.2) requires “emergency unlocking device” to be provided for every landing door, while ASME
(111.9 & 111.10) and CSA (2.12.9 & 2.12.10) require such a device only on two landings and permit it on
all other landings.
NOTE ASME and CSA Codes (2.12.6) now require unlocking devices on every landing;
b) only CSA (3.12.1.4) requires “bypass switches” to be provided in the machine room, which would bypass
interlocks or car-door-contact, disconnect normal operation and enable car-top-inspection operation, in
order to facilitate the mechanic's servicing of faulty interlocks or car-door contacts.
NOTE Now ASME/CSA require bypass switches (see 2.26.1.5 in current Codes);
c) only CEN (5.9) requires lighting of the hoistway.
3.8 Assumption 6 - horizontal forces exerted by a person
One person can exert either of the following horizontal forces at a surface perpendicular to the plane at which
the person stands:
a) static force - 300 N;
b) force resulting from impact - 1 000 N.
Static forces of short time duration may be exerted by the simultaneous deliberate acts of several people
located immediately adjacent to each other at every 300 mm interval along the width of a surface.
3.8.1 Rationale for Assumption 6
It is assumed that a person leaning against a vertical surface will exert these forces at that surface. It is further
assumed that more than one person can exert this force on a surface simultaneously. Only by relating a force
to the width of a surface on which it can be exerted, can a realistic design requirement be obtained.
10 © ISO 2006 – All rights reserved

3.8.2 Assumption 6 as applied in current standards
From Table 4 it is obvious that forces assumed in the standards are different.
Table 4 — Assumption 6 (horizontal forces exerted by a person) as applied in current standards
Assumptions CEN ASME and CSA Part 1 SA Part 3 Japan
1.0 Static force
1.1 Landing doors 300 N (7.2.3) 2 500 N 300 N (7.2.3) 1.2 kN (12.2 & No spec
[2.11.11.5.7] AS 1735.2
12.4.1
1.2 Car enclosure 300 N (8.3.2.1) 330 N [2.14.1.3] 300 N 330 N No spec
(8.3.2.1)
(23.1 &
As1735.2
23.18)
2.0 Impact on:
2.1 Landing doors Pendulum shock test when 5 000 N Pendulum shock test No spec. No spec
glass is used (7.2.3.3) See [2.11.11.8] when glass is used
Note (7.2.3.3) See Note
2.2 Car enclosure Pendulum shock test when No spec. Pendulum shock test No spec. No spec.
glass is used (8.3.2.2). when glass is used
(8.3.2.2).
3.0 Force Evenly distributed over an 100 mm x 100 Evenly distributed No spec
Door - 0.1m
distribution mm [2.11.11.5.7] over an area of 5
area of 5 cm (for the 300 Car wall –
and
N) at any place, and at cm (for the 300 N) 50 mm x 50mm
both sides (for doors) See See Note
300 mm x 300
Note
mm [2.11.11.8]
NOTE The pendulum shock tests – Hard and Soft – required are described in Annex J of EN81-2: 1998.
3.9 Assumption 7 – retardation
A person is capable of withstanding an average vertical retardation of 1 g (9,81 m/s ) and higher transient
retardations.
3.9.1 Rationale for assumption 7
The retardation which can be withstood without injury varies from person to person. Historically, the values
used in the standards (see table 5) have not been shown to be unsafe for a vast majority of people.
NOTE See 3.9.3 regarding retardation limits on emergency car stops.
3.9.2 Assumption 7 as applied in current standards
Table 5 gives a comparison of requirements based on the assumed safe retardation rates. Major differences
are noted in relation to rupture valves, plunger stops, and emergency speed limits.
No standard limits retardation in the case of car stops initiated by an electrical safety device.
Table 5 — Assumption 7 (retardation) as applied in current standards
*
Assumption CEN ASME and CSA Japan
Part 1 SA Part 3
Maximum Average
*
Retardation
Progressive Safety 1 g (9.8.4) 1 g [2.17.2.2.2] 1 g (9.8.4) 1g (33.1) 1g in vertical direction
Gear and 0.5g in horizontal
[in free fall and [with
direction
full load] counterweight
attached] (BSL-EO Art 129-10
item 2 parag.1)
Progressive Clamping 1 g, when full 1 g @ rated 1 g (9.9.4) N/A N/A
Device load (9.9.4)
load. 2 g peak >
0.04 s [3.17.3.5]
Oil Buffers 1 g (10.4.3.2) 1g [3.22] and 1 g (10.4.3.2) 1 g (9.1.5.2) 1g in vertical direction
[2.22.4.1.1] and 0.5g in horizontal
Full Load;
direction(BSL-EO Art
Type-
129-10 item 2
Examination
parag.1)
Rupture valve 1 g (12.5.5.1) 1 g 1 g (12.5.5.1) No spec. N/A
[3.19.4.7.5(b)]
2.5 g peak >
0.04 s
[3.19.4.7.5(c)]
Plunger stops 1 g (12.2.3.3.2) Rules require 1 g (12.2.3.3.2) 1 g (7.2.6) No spec.
ETSR cut speed
to 0.25 m/s
Emergency speed limit No spec. 1 g [3.25.2.2.2] No spec. No spec No spec.
Emergency car stops No spec. 1 g for certain No spec. No spec No spec.
EPD stops
[3.26.4.2]
Maximum retardation
Safety gear No spec. No spec No spec. No spec No spec.
Buffers > 2,5 g t = < 0.04 s
> 2,5 g (10.4.3.2) > 2,5 g [2.22.4.2] > 2,5 g (10.4.3.2) >2,5 g (9.1.5.3)
(JEAS-517)
(if t = Duration)
t =< 0,04 s t =< 0,04 s t =< 0,04 s t =< 0,04 s
*
NOTE: Maximum average retardation levels exceeding 1 g can occur with a lightly loaded lift during safety or buffer application.
**
NOTE: SA data apply to indirect lifts only.
NOTE 1 g = 9,81 m/s .
3.9.3 Agreed-upon points
All Standards should consider retardation limits on emergency stops initiated by an electrical safety device,
albeit based on bio-mechanical studies.
12 © ISO 2006 – All rights reserved

4 Approach to design safety for hydraulic components
4.1 Historical Background
4.1.1 Philosophical differences
This section concentrates on differences between the CEN and ASME requirements for the design of hydraulic
components. Reference to the CSA standard is made where it differs from ASME.
NOTE The second sentence is not valid any more because since 1996 there are no difference between ASME and
CSA design requirements for hydraulic components any more.
a) Differences in both design philosophy and design formulae lead to different cylinders and rams, valves,
pipes, and fittings when designed to CEN and ASME standards. Philosophical differences are as follows:
1) ASME uses the ultimate tensile strength subject to a minimum percentage elongation of the
material as a design criterion;
2) CEN uses the 0,2 % proof stress yield point as the design criterion. Percentage elongation is not
considered;
3) the working pressure is differently defined in ASME and CEN;
4) the factors of safety used are also different;
b) the differences are demonstrated by examples as illustrated by the following comparisons:
1) thickness of cylinder walls of single stage jacks (4.1.4);
2) thickness of flat cylinder base/head (4.1.5);
3) thickness of semi-elliptical cylinder head/cambered base (4.1.6);
4) thickness of ram wall for buckling (4.1.7).
4.1.2 Nomenclature
The following nomenclature is used in the two different standards:
*
Item CEN ASME
Units
Working pressure kPa — p
Full load pressure MPa p —
Inside diameter of cylinder mm D d
i
Diameter of flat head mm — d
Inside diameter of skirt mm D D
i
Outside dia. of cylinder, pipe mm D D
Wall thickness, cylinder mm e t
cy1
e
Wall thickness, flat bottom mm t
e
Wall thickness, semi-elliptical mm t
e
Additional wall thickness mm C
Design or allowable stress kPa — S
*
Item CEN ASME
Units
0.2 % proof stress Rp Y.P.
N/mm /kPa
0.2
Tensile strength R —
N/mm
m
Modulus of elasticity E —
N/mm
2 2
Cross-sectional area of plunger An A
mm /m
Slenderness ratio (dimensionless) λ —
Maximum unsupported ram length mm 1 L
Radius of gyration mm — R
Acceleration of gravity g —
m/s
n
Reeving (roping) ratio (dimensionless) Cm —
Mass of empty car kg P —
Rated load in car kg Q —
Mass of ram kg Pr —
Mass of ram head equipment kg Prh —
F
Design load on ram N —
Actual load on ram N F —
Second moment of ram area J —
Mm
n
*
If two entries, then the fìrst applies to CEN, the second to ASME.
4.1.3 Factor of Safety Comparison
ASME and CSA clause 8.2.8.5.1 (editions since 2000) requires:
1) for tensile, compressive bending and torsional loading, the plunger, cylinder and connecting
couplings shall have a factor of safety not less than 5 based on ultimate tensile strength (UTS);
2) for pressure calculations of the components that are subject to fluid pressure, including the plunger,
connecting coupling, control valves, cylinder, and rigid piping shall have a factor of safety (FOS) not
less than that calculated from:
5,04
F2=+,7 (A)
E2− ,8
where
F = Minimum FOS based on 0,2 % proof stress yield point. The minimum allowable F shall be 3;
E = Percentage Elongation in 50 mm gauge length as per ASTM Standard E8, expressed as a whole
number (eg, 20 % = 20 and 5 % = 5). The minimum allowable E shall be 5.
14 © ISO 2006 – All rights reserved

The allowable stress to be used for pressure calculations, according to ASME and CSA 8.2.8.5.2 (2000 and
later editions), shall be determined as follows:
Y.P
S = (B)
F
where
S = Allowable stress (kPa);
Y.P = Yield point based on 0,2 % proof yield stress;
F = FOS per formula (A).
CEN (12.2.1.1.1) requires that rams and cylinders be designed with a FOS of 3,91 (2,3 x 1,7), based on the
0,2 % proof stress (YP) and the full load pressure (FLP).
For calculations of tensile, compressive, bending and torsional loads the following relationship between ASME
and CEN requirements can be established:
R = 0,2 % proof stress
p0.2
ASME WP = 1,15 (CEN FLP)
ASME FOS = 5 (ASME Working Stress)
CEN FOS = 3,91 (CEN working stress at FLP) or
= 3,4 (ASME working stress at WP)
Therefore:
UTS W 5 ASME working stress
YP W 3,4 ASME working stress
(0,2 % proof stress = YP)
Nominal equality of ASME and CEN requirements would occur if:
UTS 5
== 1, 47
YP 3,4
However, the formulae employed are different in the two codes, so the comparison is more complex.
For comparisons of stresses due to pressure it is necessary to determine the FOS from the formula (A) and
the allowable stress from formula (B).
Examples of the differences between CEN and ASME/CSA are presented in the following sections 4.1.4
through 4.1.7.
NOTE 4.1.3 For further observations and suggestions regarding the factor of safety, refer to Section 4.2.1 and 4.2.4.
4.1.4 Cylinder wall thickness of single stage jacks
According to ASME and CSA (2000 and later edition, rule 8.2.8.2, the cylinder wall thickness of a single stage
jack is calculated with the following formula:
pd
t = (1)
2S
where
d inside diameter;
p working pressure;
S working (or allowable) stress;
t minimum wail thickness.
From CEN Annex K:
2,3 ×1,7 D
ep≥⋅+e (2)
cyl 0
R 2
p0.2
where
e wall thickness;
cyl
p full load pressure;
D outside diameter;
e 1,0 mm.
It was noted that e , may be 0,5 in some cases;
however it was agreed to leave it at 1,0 for the sake of simplicity.
For a valid comparison, the two formulae should be written as close, as possible in the same form, using
common parameters.
As the full load pressure (p) in Equation (2) is in fact the static pressure of the system (P ), and, based on
s
Section 2.3 in this report, the working pressure (p) in Equation
...