Ladders for escape to sea Offshore Information Sheet No. 10/2009 (Issued December 2009)
Contents
Introduction
Background
Matters to be considered if existing ladders are not to be maintained
Relevant legal requirements
References
Further information
Tables 1 and 2
Appendix A
Introduction Introduc tion This sheet advises duty holders that a change in the means of descent to sea will normally comprise a material change to the safety case , requiring submission of a revised safety case to HSE. In addition, for any such change, a number of matters will need to be considered, to ensure continuing compliance with the Offshore Installations (Prevention of Fire and Explosion, and Emergency Response) Regulations 1995 (PFEER). This sheet provides guidance on these matters, where the intention is to replace ladders to sea with an alternative means of descent to sea.
Background Fixed ladders (which may include some associated gangways and/or stairways) to sea are often provided as part of compliance with PFEER Regulation 16. Such ladders are subject to corrosion and wave impact, and there is expense and risk involved in maintaining them. Some duty holders may consider not maintaining the ladders, instead relying on alternative means of descent to sea. There are a number of matters which will need to be considered to ensure continuing compliance with PFEER. PFEER Regulation 16, and the Approved Code of Practice and Guidance1 for this regulation are given in Appendix in Appendix A. A. Other relevant PFEER Regulations are identified in Table 1. 1.
Means of escape from an offshore installation normally comprises two elements: (1) a means of descent to sea level, and (2) something which offers some protection from the elements and avoids the need to enter the sea directly. Means of descent to sea provided on UK offshore installations vary widely, depending on the installation and circumstances. Such means may include fixed ladders, retractable ladders, stairways, liferaft davits, chutes (typically Skyscape), and/or personal descender devices. Liferafts are usually provided for protection from the elements and to avoid the need to enter the sea directly. Historically, the means of descent provided have included knotted ropes or scramble nets. However, these are not regarded as a suitable primary means of descent to sea, because not all persons working offshore will have the physical capability to safely use them. HSE has not required these means of descent to be removed from offshore installations, but it is necessary to provide other means of descent to satisfy PFEER Regulation 16. Means of escape are provided as a back up system in case the arrangements for evacuation fail. Means of escape are not required to provide the same level of protection from hazards as the evacuation system, and do not necessarily include motive power or other means to enable persons to move quickly away from the installation. Note that lifeboats, gangways between installations, and marine transfer systems are normally provided as a means of evacuation, rather than a means of escape.
Matter s to be considered if existing ladders are not to be maintained 1.
To ensure continuing compliance with PFEER Regulation 16, ladders must continue to be maintained until such time as a suitable alternative means of descent to sea is in place.
2.
A change in the means of descent to sea will normally comprise a material change to the safety case. Therefore, a revised safety case will need to be submitted and accepted by HSE before the ladders are taken out of service or are allowed to deteriorate into an unacceptable condition.
3.
The workforce should be consulted about the proposed change in the means of descent. In any event, the safety representatives must be consulted in good time about the proposed revision to the safety case.
4.
The justification for replacing ladders with some other means of descent will be specific to the installation. Numerous factors can influence the decision, such as the risk levels on the installation, the size of the workforce, the extent to which means of evacuation are available (which can influence the number of persons who may require to escape), and the location of jacket legs in relation to the hydrocarbon hazards (ladders on legs in the process area have reduced availability in the event of a hydrocarbon fire). PFEER Regulation 5 requires the duty
holder to carry out an assessment in relation to evacuation, escape, recovery and rescue. The assessment should address the types, capacity, and locations of means of escape to sea, and will need to be revised if the intention is to replace the ladders to sea with some other means of descent to sea. 5.
The revised PFEER Regulation 5 assessment should include an examination of whether the total package of risk associated with the alternative means of descent to sea is less than or equal to the total package of risk associated with maintaining ladders to sea. Risks which may contribute to the total package of risk are (i) risk from use of the system in an emergency, (ii) risk due to potential unavailability of the system, (iii) risk during training to use the system, and (iv) installation and maintenance risk. Replacing ladders with an alternative means of descent to sea which leads to an increase in the total package of risk is not acceptable.
6.
If ladders are not to be maintained, a duty holder must be able to show that it is not reasonably practicable to do so. Normally to do this the duty holder will need to carry out a cost benefit analysis (CBA), which compares the costs of maintaining ladders with the residual risk reduction expected if ladders are provided. Ladders should continue to be maintained unless it can be shown that these costs are disproportionate compared with the risk reduction from retaining the ladders. When determining the costs and risks for inclusion in the CBA, the duty holder should fully consider all reasonable alternative ways of continuing to provide ladders to sea at minimum risk and cost. The alternatives might include, for example, the fitting of fixed retractable ladders, or replacement of corroded ladders with pre-assembled modular ladders, or provision of improved corrosion protection of existing ladders.
7.
It is accepted that quantification of the above risks will require some broad assumptions and judgements - offshore emergencies requiring use of escape systems are rare so there is little hard data on the effectiveness of different means of escape. For illustrative purposes only, Table 2 provides an example of a qualitative risk comparison between ladders to sea and personal descender devices. However, the CBA will need to include some quantification of risk.
8.
PFEER Regulation 16 requires that means of descent be available for all those persons on the installation who may need to escape from the installation. This has implications both for the numbers and locations of means of descent, and will depend on the numbers and likely locations of persons on the installation. The number who may need to escape at any one time is likely to be less than the total POB, but the duty holder will need to ensure appropriate access to sufficient means of descent to sea both for the largest groups who may need to escape (mass escape) and for isolated individuals. For example, the largest group who need to escape may be the full complement of a lifeboat which is found to be unavailable. In some cases, it may be appropriate to provide two means of descent to sea, one for mass escape at specific locations, and another more distributed means of escape for individuals.
9.
The means of descent will need to deliver escapees to a point at which they can board a liferaft (assuming that liferafts have been selected as the means of providing protection from the elements, and avoiding the need to enter the sea directly).
10. If ladders are no longer in a safe condition, the duty holder must ensure that appropriate arrangements are in place (i) to fully inform the workforce, (ii) to prevent use of the ladders, and (iii) to ensure that any remaining parts of the ladders do not present a risk should they fall off. 11. In addition to the requirements related to PFEER Regulations 5 and 16, the duty holder must ensure that the replacement means of descent complies with other relevant PFEER Regulations, as per Table 1.
Relevant legal requirements Offshore Installations (Prevention of Fire and Explosion, and Emergency Response) Regulations 1995 (PFEER), Regulations 5, 6, 8, 14, 16, 18 and 19. Offshore Installations (Safety Case) Regulations 2005 Regulation 14(2)
References Further information Any queries relating to this information sheet should be addressed to: Health and Safety Executive Hazardous Installations Directorate Offshore Division Lord Cullen House Fraser Place Aberdeen AB25 3UB Tel: 01224 252500 This information sheet contains notes on good practice which are not compulsory but which you may find helpful in considering what you need to do
Tables 1 and 2 Table 1. PFEER Regulati ons applicabl e to t he means of descent t o sea (See PFEER Regulations for precise wording) PFEER Regulation
Relevance to means of descent to sea
5 Assessment
See main text of this Information Sheet.
6 Preparation for emergencies
Persons must be adequately trained in use of the means of descent. Adequate written information must be provided about the means of descent.
8 Emergency response plan
The use of the means of descent must be adequately covered in the Emergency Response Plan, and associated drills and exercises.
14 Muster areas etc
There must be safe access to escape points. Designated escape points must be kept unobstructed, provided with adequate emergency lighting, and marked with a suitable sign.
16 Means of escape
See main text of this Information Sheet.
18 Suitability of personal protective equipment for use in an emergency
This regulation places responsibility on the duty holder to provide suitable personal protective equipment for use in an emergency. The means of descent to sea and any protective clothing provided for use in an emergency must be compatible.
19 Suitability and condition of plant
The means of descent must be suitable for the purpose for which it is used or provided. There must be arrangements to maintain the means of descent in efficient working order and good repair. It is expected the means of descent will be designated as a safety critical element, and as such must be covered by a suitable written scheme for the systematic examination by a competent and independent person (the ICP).
Table 2. Example of a qualitative ris k comp arison b etween fixed ladders and personal descender devices Risk
Ladder
Personal descender devices
Risk during use
Low risk, but persons could "freeze" or fall off the ladder.
More complex to use, and greater scope for error in use during emergency conditions. However, this risk can be minimised by providing thorough training (and refresher training) for every person on board, including visitors; such training to include practical use of the descender unit by person wearing the installation survival PPE.
Quick to use provided only a few persons need to use the ladder. Simple to use, no training required (except for deployment of retractable ladders, if fitted). Escape takes place at fixed points, which can be suitably illuminated. It can be assured that some survival PPE and a liferaft will be available at those points. The standby vessel will also be familiar with these points.
More complex to use, and greater scope for error in use during emergency conditions. However, this risk can be minimised by providing thorough training (and refresher training) for every person on board, including visitors; such training to include practical use of the descender unit by person wearing the installation survival PPE. Not quite so quick to use as a ladder, but speed is unaffected by number of persons escaping. Potentially more doubt about location of escapees, and less certainty of access to emergency lighting, survival PPE, and liferaft, but these issues can be resolved if descender stations are provided which include an adjacent liferaft, survival PPE, identified descender connection points, and emergency lighting. Also, descender units should be equipped for painter connection.
Risk due to unavailability of means of escape
Variable availability depending on (i) quality of maintenance arrangements, and (ii) siting of ladders in relation to hazards. An unrevealed failure of a ladder is also possible.
Good availability, provided sufficient units are provided in suitable locations.
Likelihood of non-availability can be reduced by effective maintenance, and suitable location of ladders.
Training risks
Very small.
There are training risks, but these can be made very small by effective design and management of training.
Risks from installation and maintenance
There are risks from installation and maintenance, but these can be minimised by good design (eg fit retractable ladders where appropriate, eg fit modular alternative ladders, eg maximise corrosion protection of ladder and attachment points), and by good management of maintenance activities.
Very small.
Appendix A Guidance and the Appr oved Code of Practice associ ated with PFEER Regulati on 16 (taken from HSE Book s doc ument L65 Secon d Ed.) PFEER Regul ation 16 "Means of escape" The duty holder shall provide such means as will ensure, so far as is reasonably practicable, the safe escape of all persons from the installation in case arrangements for evacuation fail.
Guidance The regulation requires the duty holder to provide means of escape so that persons may escape from the installation in the event of the failure of the evacuation system in a catastrophic incident when a planned and orderly evacuation cannot be achieved. This paragraph explains some of the terms relevant to the regulation:
escape means the process of leaving the installation in an emergency when the evacuation system has failed; it may involve entering the sea directly and is a 'last resort' method of getting persons off the installation;
means of escape cover items which assist with descent to the sea, such as davit-launched life-rafts, chute systems, ladders, and individually controlled descent devices; and items in which personnel can float on reaching the sea, such as throw-over life-rafts.
Ap pr ov ed Co de o f Pr act ic e (ACOP) Duty holders should select means of escape on the basis of their contribution to reducing the risks of those who may have to escape from the installation to as low as is reasonably practicable. This means that duty holders should give preference to means which offer some protection from the elements and avoid the need to enter the sea directly. In addition, sufficient means of descent to the sea should be provided on all installations, including fixed ladders or stairways, where reasonably practicable, and personal devices for controlled descent. The duty holder should provide enough means of escape to ensure that they are available for all personnel who may have to use them. Duty holders should also ensure that means of escape and any protective clothing provided for use in an emergency are compatible.
