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A detailed ergonomic assessment of ladder climbing

Key risks (short- and long-term) to technicians in the offshore wind industry

26/01/2018 Dr Gemma Milligan, Dr Joseph O’Halloran & Prof. Mike Tipton

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1. Literature Review

2. Task Analysis

3. Ergonomic Assessment

4. Thermal Aspects

Answering the brief :

Provide a detailed ergonomics assessment, identifying the key risks to

technicians (short- and long-term) associated with ladder climbing in the

offshore wind industry.

Objective: Conduct a review and analysis of existing literature on ladder climbing and the effects of

this activity on the human body (long term and short term).

Literature Review

Physiological

Musculoskeletal

Biomechanical

Health risks

34

Studies

Results & Practical Application:

Hand positioning

Rails vs Rungs

Slip risks

Force application and climbing technique

Toe clearance

Slip risks

Current recommendations

Physical demands

Ladder pitch

Injuries

Risk factors

Literature Review

Results & Practical Application:

The results demonstrated a lack of research on the specific

ergonomic risks associated with working in the wind power

industry.

Previous assessments on ladder climbing have focused on

short duration climbs involving multiple ascents and descents

The short nature of the climbs makes it inadvisable to

generalise the findings to Wind Technicians (WT)

The lack of relevant existing literature for WT ladder climbing

vindicates the current project

Literature Review

Objective: To determine whether the current industry physical fitness standards are adequate to

assess a technician’s ability to undertake the expected level of ladder climbing.

Methods: The task analysis was completed through:

Observations of WT performing tasks

The research team undertaking tasks

Reviewing operational manuals

Using a focus group with an expert panel

Critical Task Analysis

Results & Practical Application:

Five critical tasks were perceived to be the most physically demanding for WT:

1. Transfer from the vessel to the TP

2. Ascent of the internal ladder

3. Manoeuvre through hatches

4. Torque and tensioning

5. Haul a casualty up the tower

Critical Task Analysis

Results & Practical Application:

Not all relevant physical components (e.g. strength, muscular endurance, flexibility) are assessed by

the current medical guidelines

Critical Task Analysis

Aerobic

Mobility

There is no standardisation across organisations for the assessments that

are used (e.g. measurement of aerobic fitness)

Objective: To undertake a detailed ergonomic assessment of ladder

climbing, identifying the key risks, and determine if the current

assessments of fitness are appropriate for predicting ladder climbing

ability

Methods:

7 WT and 10 novice climbers undertook 3 x 120 m (4 x 30 m

climbs separated by a rest to work schedule of 1:1), at a self

selected pace, climbs separated by approximately 1.5 hrs

Ergonomic Assessment

Results & Practical Application:

The comparison of WT to novices showed that technique and experience:

Improves performance

Reduces the physiological burden (effort and thermal response)

Maintains optimal movement patterns for longer

Ergonomic Assessment

Results & Practical Application:

As fatigue increased with multiple climbs, toe

clearance on the ladder was reduced

Changes where observed in the shoulder joint which

suggested that as fatigue increased participants

changed their technique to reach higher with their

arms

Novices demonstrated less range of movement

through the hips, and a higher proportion of muscle

activation in the upper body than the WT

Ergonomic Assessment

Results & Practical Application:

Wearing a sea survival suit changes movement patterns such that WT are less efficient

(increased demand and heat production)

Grip strength: - 40 % to 50 %; Grip endurance: - 32 % to 49 % reduction

The data on muscle activity, grip strength and grip endurance supported the subjective feedback

that the reason for resting during the ladder climb was fatigue in the forearms. This fatigue was

noted to last several days in some participants

Ergonomic Assessment

Thermal Aspects

Objective: To investigate the thermal stress of

technician whilst climbing, and their ability to perform

their work safely after multiple ladder climbs.

Methods:

Temperature data were collected on seven WT,

during the 3 x 120 m climbs

Mechanical efficiency and total heat production

were calculated for climbing in a sea survival

suit (Climb 1) and overalls (Climb 2 & 3)

Thermal Aspects

Results & Practical Application:

Figure 3. Deep body temperature data for two participants in each condition. Climb 1 with the addition

of a sea survival suit.

Thermal Aspects

Results & Practical Application:

Table 1. Estimated time to reach a deep body temperature of 38.5 °C. Calculated on the basis of

direct measurements in the present study, as well as calculated theoretical maximum changes (worst

case/no heat loss) from heat production data.

Condition Time to 38.5 °C (min)

Survival Suit using Tpill data from current study 45.5

Overalls using Tpill data from current study 62.5

Survival Suit using calculated worst case scenario (no heat loss)

14.3

Overalls using calculated worst case scenario (no heat loss)

14.2

Take Home Messages

1. Little in the existing literature for WT

2. The most physically demanding tasks of WT have been identified

3. The physical demands of WT are not all currently assessed in the evaluation of fitness

4. With fatigue, shoulder flexion increases (over-reaching) and toe clearance decreases (trip hazard)

5. Following ladder climbing manual function is significantly impaired for a period of time

6. WT climb ladders more efficiently than novices, correct ladder climbing and technique should be

taught

7. WT, allowed to rest and climb as they wish, should not experience a direct problem with

hyperthermia

8. WT, particularly wearing survival suits, may experience problems indirectly associated

with hyperthermia. Appropriate work/rest schedules, clothing polices and hydration

polices should mitigate these problems

Recommendations

It is recommended that future work focus on three main areas:

1. Training packages

2. Review of fitness and selection policies

3. Work/rest schedules

4. Review policies on cooling and hydration

Thank you for listening

ANY QUESTIONS?

28 September 2013 76