1、 I n t e r n a t i o n a l T e l e c o m m u n i c a t i o n U n i o n ITU-T L.92 TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU (10/2012) SERIES L: CONSTRUCTION, INSTALLATION AND PROTECTION OF CABLES AND OTHER ELEMENTS OF OUTSIDE PLANT Disaster management for outside plant facilities Recommendatio
2、n ITU-T L.92 Rec. ITU-T L.92 (10/2012) i Recommendation ITU-T L.92 Disaster management for outside plant facilities Summary Recommendation ITU-T L.92 gives an overview of the technical considerations for protecting outside plant facilities from natural disasters. Disaster management for outside plan
3、t facilities such as cables, poles and manholes are introduced, and countermeasures for natural disasters such as earthquakes, strong winds and floods are described. In the appendices, Korean and Japanese experiences of disaster management are respectively introduced. Also, answers to a related ques
4、tionnaire are also included to provide basic information about natural disasters around the world. The objective of this Recommendation is to share observations, knowledge, experiences and practices internationally, so that local engineering practices can be adopted to improve the disaster resistanc
5、e performance of outside plant facilities. History Edition Recommendation Approval Study Group 1.0 ITU-T L.92 2012-10-29 15 Keywords Disaster management, earthquake, flood, landslide, natural disaster, outside plant facilities, tsunami. ii Rec. ITU-T L.92 (10/2012) FOREWORD The International Telecom
6、munication Union (ITU) is the United Nations specialized agency in the field of telecommunications, information and communication technologies (ICTs). The ITU Telecommunication Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying technical, operating and tari
7、ff questions and issuing Recommendations on them with a view to standardizing telecommunications on a worldwide basis. The World Telecommunication Standardization Assembly (WTSA), which meets every four years, establishes the topics for study by the ITU-T study groups which, in turn, produce Recomme
8、ndations on these topics. The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolution 1. In some areas of information technology which fall within ITU-Ts purview, the necessary standards are prepared on a collaborative basis with ISO and IEC. NOTE In this Recommend
9、ation, the expression “Administration“ is used for conciseness to indicate both a telecommunication administration and a recognized operating agency. Compliance with this Recommendation is voluntary. However, the Recommendation may contain certain mandatory provisions (to ensure, e.g., interoperabil
10、ity or applicability) and compliance with the Recommendation is achieved when all of these mandatory provisions are met. The words “shall“ or some other obligatory language such as “must“ and the negative equivalents are used to express requirements. The use of such words does not suggest that compl
11、iance with the Recommendation is required of any party. INTELLECTUAL PROPERTY RIGHTSITU draws attention to the possibility that the practice or implementation of this Recommendation may involve the use of a claimed Intellectual Property Right. ITU takes no position concerning the evidence, validity
12、or applicability of claimed Intellectual Property Rights, whether asserted by ITU members or others outside of the Recommendation development process. As of the date of approval of this Recommendation, ITU had not received notice of intellectual property, protected by patents, which may be required
13、to implement this Recommendation. However, implementers are cautioned that this may not represent the latest information and are therefore strongly urged to consult the TSB patent database at http:/www.itu.int/ITU-T/ipr/. ITU 2013 All rights reserved. No part of this publication may be reproduced, b
14、y any means whatsoever, without the prior written permission of ITU. Rec. ITU-T L.92 (10/2012) iii Table of Contents Page 1 Scope 1 2 References. 1 3 Definitions 1 3.1 Terms defined elsewhere 1 3.2 Terms defined in this Recommendation . 2 4 Abbreviations and acronyms 2 5 Conventions 2 6 Natural disa
15、sters . 2 6.1 Typical natural disasters . 2 6.2 Disaster management 3 6.3 IPOCM . 3 7 Technical considerations 4 7.1 Introduction 4 7.2 Earthquakes 4 7.3 Tsunami 5 7.4 Floods . 5 7.5 Strong winds . 5 8 Disaster management for outside plant facilities 5 Appendix I Korean experience . 8 I.1 Strong win
16、ds . 8 I.2 Earthquakes 8 I.3 Floods . 10 Appendix II Japanese experiences earthquake countermeasures for underground facilities 11 II.1 Introduction 11 II.2 Earthquake countermeasures 11 II.3 Example of evaluating the seismic performance of outside plant facilities . 12 Appendix III Answers to the q
17、uestionnaire on “Technical considerations on protecting outside plant facilities from natural disasters“ 14 Bibliography. 17 iv Rec. ITU-T L.92 (10/2012) Introduction Recently, natural disasters such as earthquakes and floods have occurred more frequently. Outside plant facilities such as manholes a
18、nd poles are occasionally damaged by these disasters, and as a result, telecommunication services stop. In order to minimize the damage and/or to safely protect outside plant facilities, appropriate disaster management is needed. This Recommendation provides typical examples of disaster management i
19、ncluding technical considerations. Rec. ITU-T L.92 (10/2012) 1 Recommendation ITU-T L.92 Disaster management for outside plant facilities 1 Scope This Recommendation: describes typical natural disasters and events such as earthquakes, tsunamis, floods, strong winds, etc.; describes typical disaster
20、management for outside plant facilities; deals with outside plant facilities such as cables and associated hardware (cable tunnels, underground conduits, manholes, poles, towers, cabinets, etc.); provides technical considerations for protecting outside plant facilities from natural disasters. Teleco
21、mmunication buildings including indoor facilities are out of the scope of this Recommendation. The protection of cables and plants against lightning is dealt with by ITU-T K.47. 2 References The following ITU-T Recommendations and other references contain provisions which, through reference in this
22、text, constitute provisions of this Recommendation. At the time of publication, the editions indicated were valid. All Recommendations and other references are subject to revision; users of this Recommendation are therefore encouraged to investigate the possibility of applying the most recent editio
23、n of the Recommendations and other references listed below. A list of the currently valid ITU-T Recommendations is regularly published. The reference to a document within this Recommendation does not give it, as a stand-alone document, the status of a Recommendation. ITU-T K.47 Recommendation ITU-T
24、K.47 (2012), Protection of telecommunication lines against direct lightning flashes. ITU-T L.81 Recommendation ITU-T L.81 (2009), Monitoring systems for outside plant facilities. ITU-T Y.1271 Recommendation ITU-T Y.1271 (2004), Framework(s) on network requirements and capabilities to support emergen
25、cy telecommunications over evolving circuit-switched and packet-switched networks. 3 Definitions 3.1 Terms defined elsewhere This Recommendation uses the following terms defined elsewhere: 3.1.1 response spectrum b-IEC 60068-2-57: Plot of the maximum response to a defined input motion of a family of
26、 single-degree-of freedom bodies as a function of their natural frequencies and at a specified damping ratio. 3.1.2 soil liquefaction b-ASCE: Soil liquefaction is a phenomenon whereby a soil loses strength and stiffness during an earthquake, causing it to behave like a liquid. Surface-supported stru
27、ctures have settled several feet below grade, and buried tanks have floated to the surface. 2 Rec. ITU-T L.92 (10/2012) 3.2 Terms defined in this Recommendation This Recommendation defines the following term: 3.2.1 earthquake-resistance performance: The capacity to withstand a certain level of shaki
28、ng without excessive damage. 4 Abbreviations and acronyms This Recommendation uses the following abbreviations and acronyms: IPOCM Incident Preparedness and Operational Continuity Management NATM New Austrian Tunnelling Method TBM Tunnel Boring Machine 5 Conventions None. 6 Natural disasters 6.1 Typ
29、ical natural disasters Typical natural disasters which may potentially affect outside plant facilities are listed in Table 1. Table 1 Typical natural disasters Natural disasters Typical effects Earthquakes Destruction of all outside plant facilities; duct bursts and disconnection of cables. Tsunami
30、Damage to all outside plant facilities; damage to central office power supplies in coastal areas. Flash floods/floods Immersion of cable tunnels; potential cable damage; liquid penetration into cables. Forest fires Burned down telecommunication poles; disconnection of aerial cables. Hurricanes/torna
31、does/typhoons/wind storms Falling telecommunication poles or towers; physical damage to aerial structures; disconnection of aerial cables. Landslides Destruction of underground ducts; failure of retaining structures. Severe cold, snow, ice or heat Destruction of telecommunication equipment. Rec. ITU
32、-T L.92 (10/2012) 3 6.2 Disaster management Disaster management activities can be grouped into four phases as follows: Mitigation (prevention): activities that actually eliminate or reduce the probability of a disaster. Preparedness: activities prior to disasters that are used to support the prevent
33、ion of, mitigation of, response to, and recovery from disasters. In this phase, plans are developed to save lives and minimize disaster damage (for example, installing early warning systems). Response: activities following a disaster. These activities are designed to stabilize the situation and to r
34、educe the probability of secondary damage. Recovery: activities necessary to return all systems to normal or better (for example, rebuilding destroyed property, or the repair of other essential infrastructure). 6.3 IPOCM Incident preparedness and operational continuity management (IPOCM) provides a
35、basis for understanding, developing and implementing incident preparedness and operational continuity within an organization. This is a tool to allow public or private organizations to consider the factors and steps necessary to prepare for an unintentionally, intentionally, or naturally caused inci
36、dent (disruption, emergency, crisis or disaster) so that it can manage and survive the incident and take the appropriate actions to help ensure the organizations continued viability. Figure 6-1 explains the concept of incident preparedness and IPOCM. Figure from ISO/PAS 22399:2007 reproduced with th
37、e permission of ISO. Copyright remains with ISO. Figure 6-1 Concept of incident preparedness and IPOCM 4 Rec. ITU-T L.92 (10/2012) 7 Technical considerations 7.1 Introduction The objective of this Recommendation is to provide technical considerations when deploying outside plant facilities. These wi
38、ll include design criteria and standard methods that have been already described in other Recommendations or ITU-T handbooks or manuals. 7.2 Earthquakes 7.2.1 General Outside plant facilities may be damaged during earthquakes. Telecommunication services may be lost because of damage to a central off
39、ice, underground conduits and overhead cables. Therefore, seismic design standards for outside plant facilities are needed to improve their earthquake performance. In addition, it is necessary to perform an initial evaluation of the earthquake hazard and outside plant facilities vulnerability. 7.2.2
40、 Cables Telecommunication cables are an important part of the infrastructure and they have to meet a set of requirements. These requirements are intended to protect the cables from the hostile outside plant environment, which includes earthquakes. It is recommended that cables should have good seism
41、ic performance. It is desirable that cables have enough length at manholes so as not to be cut due to ground settlement by earthquakes. 7.2.3 Poles Poles have several failure modes: falling, sinking and breaking. Poles fall to the ground when the bearing capacity of foundation is weak. In liquefied
42、soils, poles sink into the soil. Poles can also be broken at the weakest point. The failure of the pole is attributed to ground motions or to being pulled over when an adjacent pole fails. Appropriate countermeasures should be applied according to these failure modes. 7.2.4 Towers Towers are lattice
43、 steel structures which are used to support telecommunication cables. The design criteria for towers include both seismic and wind loads, but wind loads usually control the design. Earthquake resistance design for towers can be substituted by wind resistance design, if the wind load is proved to be
44、greater than the earthquake load. On building supported towers, however, the dynamic amplification introduced by the building should be evaluated. Though wind loads usually control tower design, earthquake performance evaluation is explicitly considered. 7.2.5 Manholes, hand-holes and conduits Manho
45、les, hand-holes and conduits are critical components of outside plant facilities. Manholes, hand-holes and conduits are usually damaged during earthquakes. When a conduit is damaged, water can penetrate the closure and small flaws in cables will eventually allow water to enter and degrade cable perf
46、ormance. Manholes are damaged when soil liquefaction occurs. The soil around the manhole liquefies and loses its shear strength, and as a result, the manhole can sink or float, breaking conduits connected to the manhole. 7.2.6 Cable tunnels There are two types of cable tunnels: open cut box cable tu
47、nnel and shield/NATM/TBM cable tunnel. Typically, cable tunnels have a higher reliability due to their higher rigidity compared with buried conduits. A shield tunnel has a higher reliability due to its deep construction compared with an open cut cable tunnel, because it is not affected by liquefacti
48、on and subsidence. Rec. ITU-T L.92 (10/2012) 5 7.3 Tsunami A tsunami consists of a series of sea waves and is usually caused by a massive submarine earthquake. Central offices and outside plant facilities in coastal areas may suffer serious damage. It takes a long time to repair damaged telecommunic
49、ation services at central offices due to the wide variety of specialized equipment typically installed there. There is a need to design alternate trunk cable routes that can be used to sustain telecommunication services when a large portion of the trunk network is degraded. In addition, it is important to prevent water damage in manholes, hand-holes and cable tunnels and to prevent water damage to the power supplies of buildings and to have backup power supplies available for use during power supply failures. 7.4 Floods Outside pl
