Drop block or drop line: when do you choose which?

Choose a fall-arrest lanyard with energy absorber (EN 355) if you work in one place or move along anchor points, and there is enough free space below you: with the Petzl ABSORBICA-I 80, that is 3.58 m below your feet in the worst-case scenario. Choose a fall arrester (EN 360) if you need to move further from the anchor point or if the free space is tight: the line rolls with you and locks immediately, which means the Tractel Blocfor 6 ESD requires 2.40 m of free space with an anchor above you. The downside is that a fall arrester is heavier, requires an anchor above you or at least at hip height, and must undergo an annual safety inspection with written approval.

What is the difference between a fall arrester and a fall-arrest lanyard?

A fall-arrest lanyard is a line of fixed length with an energy absorber. If you fall, you first fall freely until the line is taut. Then the absorber tears open and brakes the fall. Petzl states a maximum arresting force of 6 kN for the ABSORBICA-I and an average of 5 kN.

A fall arrester (in the standard, an automatically locking fall protection device) has a line or webbing on a spring-loaded spool. During work, the spring keeps the line taut. In the event of a fall, a pawl system immediately locks the spool, and a webbing absorber limits the force to less than 6 kN. You therefore do not fall the entire line length, but only the braking distance.

Both are a means of connection between your fall harness (EN 361) and an anchor point. The harness, the anchor point, and the free space together determine whether the system works.

How much free space do you need?

Free space is the space below your feet that must be empty, so that you do not hit the ground or an obstacle in the event of a fall. This is where the biggest difference lies:

• ABSORBICA-I 80 (maximum 1 m including carabiners): in the longest fall, with the anchor at foot height, the free fall is 2.00 m, the absorber tears open by 0.58 m, and Petzl adds a 1 m margin. Total 3.58 m up to 100 kg and 3.87 m from 100 to 140 kg.
• Blocfor 6 ESD vertically, with the anchor above you: 1.4 m fall distance plus a 1 m margin, total 2.4 m. If you stand 3 m to the side of the vertical line under the anchor, an additional 0.5 m is added due to the swing: 2.9 m.

Note: the value of the fall-arrest lanyard is the worst-case scenario. If the anchor is above you, the fall is shorter. The value of the fall arrester applies only with the anchor above you. If you are attached to a flexible horizontal anchor line (EN 795 type C), you add the deflection of that line to both. How to calculate the free space of a fall-arrest lanyard exactly, you can read in Free fall space: how much height does a fall-arrest lanyard really need?

Fall arrester and fall-arrest lanyard side by side

Feature	Fall-arrest lanyard: Petzl ABSORBICA-I 80	Fall arrester: Tractel Blocfor 6 ESD
Standard	EN 355	EN 360:2023
Length	0.7 m, maximum 1 m with carabiners	6 m webbing of 25 mm
User weight	60 to 140 kg	50 to 150 kg
Free space below your feet	3.58 m up to 100 kg, 3.87 m up to 140 kg (anchor at foot height)	2.4 m (vertical, anchor above you, directly below)
Anchor point	Preferably above you, EN 795, at least 12 kN	If possible above you, at least at hip height, EN 795, at least 12 kN
Own weight	170 g	2.42 kg
Arresting force	Maximum 6 kN, average 5 kN	Less than 6 kN
Periodic inspection	At least every 12 months by an authorized person	At least every 12 months, with written approval
Lifespan	10 years	No end date with annual inspection; textile replaced after 20 years at the latest by an authorized service center

When do you choose a fall-arrest lanyard?

A fall-arrest lanyard is suitable for work where you stay close to the anchor point, and for climbing along a structure.

• Work in one place or along a line without intermediate anchors. For this, a single line, such as the ABSORBICA-I, is intended.
• Climbing along a structure or passing anchors. Then you need a double line, such as the ABSORBICA-Y MGO, according to Petzl.
• Light and compact. A fall-arrest lanyard weighs a fraction of a fall arrester and hinders you less during climbing work.

A fall-arrest lanyard also has limits. The longer the line, the more room to move, but also the longer the fall and the more free space you need. Petzl calls the adjustable ABSORBICA-I VARIO a way to keep the line and thus the fall short. Do not hook the free end of a line back to your harness: according to Petzl, that limits the operation of the absorber.

When do you choose a fall arrester?

A fall arrester is suitable for work under a fixed anchor point where you need more room to move, or where the space below you is limited. Tractel calls the Blocfor 6 ESD for maintenance work on scaffolding, roofs, and terraces. Tractel does state strict conditions for the Blocfor:

• Never extend a fall arrester with a fall-arrest lanyard or loop, not on the harness side and not on the anchor side.
• Do not work further than 20° from the vertical line under the anchor point.
• Do not use the fall arrester on sloping or unstable surfaces: it may not lock there.
• Do not use it as a positioning line, lifting device, or cargo strap, and always by one person.
• Use only a version tested for that purpose over a roof edge. For the Blocfor, that is the 6 ESD and the galvanized 10 and 20 m; the stainless steel versions and the rope version not. The conditions for that are in Fall protection on a roof.

There is also a short fall arrester. The Blocfor 1.8B ESD has 1.80 m webbing, weighs 1.33 kg, and locks within 100 mm fall distance according to Tractel. If the work is such that a rescuer must be able to retrieve you after a fall, there is also a fall arrester with a built-in rescue winch, the Blocfor R EVO.

How to choose in five steps

1. Can it be done without a harness? A fence, railing, or work floor takes precedence over personal fall protection.
2. Where is the anchor point? Above you: both are possible. At foot height: a fall-arrest lanyard, with the free space from the table. Tractel wants a fall arrester above you as much as possible and at least at hip height.
3. How much do you need to move? Close to the anchor, within the length of the line: fall-arrest lanyard. More meters under one anchor: fall arrester. Climbing along a structure: double fall-arrest lanyard.
4. How much space is there below you? Measure from your feet to the first obstacle and compare with the value in the user manual, including your weight with tools.
5. Is an edge or a rescue plan needed? Different rules apply for a fall over an edge. You always need a rescue plan.

Frequently asked questions

Can you extend a fall arrester with a fall-arrest lanyard?

No. Tractel prohibits extensions such as fall-arrest lanyards or loops between the Blocfor and the harness and between the Blocfor and the anchor point.

Is a fall arrester safer than a fall-arrest lanyard?

Not in general. A fall arrester requires less free space with an anchor above you, but has more conditions. A fall-arrest lanyard is simpler and lighter. The situation at the workplace determines the choice.

Can a fall arrester be horizontal over an edge?

Only if the user manual allows it. For the Blocfor ESD/EVO series, this applies to the 6 ESD and the galvanized versions, with a free space of 5 m below the edge.

How often do you need to have a fall arrester or fall-arrest lanyard inspected?

Both at least every 12 months. Tractel requires written approval for the Blocfor; without an inspection in the past 12 months, you may not use it. Also check both yourself before each use. Read more about this in Fall protection inspection.

What do you do after a fall?

Both have a fall indicator. If it is torn on the ABSORBICA or visible on the Blocfor, the product has arrested a fall. Take it out of use: Petzl states the line is retired and Tractel states for the Blocfor to be taken out of use and destroyed.

Products and further reading

• Petzl ABSORBICA-I fall-arrest lanyard with energy absorber
• Petzl ABSORBICA-I VARIO adjustable fall-arrest lanyard
• Petzl ABSORBICA-Y MGO double fall-arrest lanyard
• Tractel Blocfor ESD fall arrester 6, 10 and 20 m and Blocfor 1.8B ESD
• All fall arresters and all fall-arrest lanyards and energy absorbers
• Read also: Calculate free fall space and Fall protection on a roof

Sources: Petzl user manual ABSORBICA-I/Y (L0047000C), product page ABSORBICA-I 80 and Tech Tip "Which type of fall-arrest lanyard to choose?" on petzl.com; Tractel user manual Blocfor ESD & EVO ESD (257985, July 2026), technical data sheets Blocfor 6 ESD (T-2672, 03/2026) and Blocfor 1.8B ESD (T-2546); Arbobesluit article 3.16 (wetten.overheid.nl). Photos: Petzl. Diagram: Hef en Hijs Online. Last checked on November 14, 2026. This article does not replace the user manuals of the ABSORBICA and the Blocfor.