Flexible lifting strap — How to Read the Table, and What the Word Adds

1. The Article, and the Word in Front of It

A flexible lifting strap is a woven article with no rigid member in it and no hardware in the load path: it bends, it folds, it lies into a curve, and it can be dressed round a load by hand. Flexibility is a property of the construction rather than a grade, which is why it appears in the name of several different articles on this site - the flat strap, the circular belt, the wrapped sling - and why the same word carries no figure with it.

The flexible lifting strap as supplied. This is the factory's own photograph, and it is placed before the table rather than after it on purpose: what the photograph shows is the reason the table can be read the way this page reads it, because a soft article conforms to a load rather than forcing the load to suit the article.

2. How to Read the Parameter Table on This Page

The table below is the factory's own specification sheet, and it is worth reading in the order the columns are printed rather than by finding the biggest number on it. Every row is one item number; the first column is that item number, the second is its colour, and the rest describe what the item will do.

Two of those columns are the ones that get misread. The breaking load is not the figure a lift may be planned from, and the three mode columns are not three ways of getting more out of the article: they are three ways of using it, and only one of them applies to any given lift. If the lift is a choke, the figure is the choke column; if it is a two-leg arrangement, the figure is the column for the angle the legs will actually make. The angle on the drawing and the angle on site are rarely the same, and the lower column is the one to plan from.

3. Choosing an Item Number

The rows are arranged by capacity, and the usual mistake is to choose from the left-hand end of the row - the largest number - because it is the largest number. The right end of the row is what the lift will actually need.

One consequence is worth stating plainly, because it is the reason this page exists next to a table: the table answers a capacity question, and only a capacity question. Everything else about the lift - the surface, the edges, the temperature, the chemicals, the angle on site, the way the article is dressed - is decided outside the table, and it is decided before the item number is chosen rather than after.

4. The Three Ways of Lifting, and Why the Figures Fall

The three mode columns are the clearest thing on the sheet and the least used. They encode one idea: the same article holds different figures depending on how it is attached to the load and how the legs sit. A choke wraps the article round the load and passes it through itself, which concentrates the load at the point of contact and reduces the figure to eight tenths. A two-leg arrangement shares the load between the legs, and the share each leg carries depends on the angle: at 45 degrees the legs are doing well out of the geometry, and at 90 degrees each leg is taking a much larger share of the load than half, which is why the figure falls.

The published practice goes further than the sheet does: horizontal angles below 30 degrees are outside it unless the manufacturer says otherwise, and a choke is rated from the table only provided the angle of choke is 120 degrees or more. Where a lift sits outside the columns, the figure comes from us rather than from the row, which is what the enquiry is for.

5. Colour, Identification and the Marking

The table lists a colour for each item, and the colour is doing the same job here as it does on the rest of this site: it is a cue for sorting and recognition, not a figure. Above ten tonnes the published colour code stops separating values altogether, so on the heavier rows of this table the colour identifies a class and the marking carries the capacity. The colour flat industrial lifting belt page sets out what the colour system is for and where it fails.

6. The Duty Envelope That the Table Does Not Show

Nothing on the parameter sheet is about temperature or chemistry, and both decide whether a row of it can be used at all. The envelope follows the fibre, and for polyester and polyamide the published guides give minus 40 to plus 100 degrees C, the guidance for synthetic slings gives 90 degrees C as the upper figure, and the regulation gives 180 degrees F for polyester and nylon. Work should be to the lowest of the figures that apply to the article and the market it is sold into, and the WLL 150T polyester round sling page sets out how those figures are reconciled. Chemistry is the other half: nylon is excluded where acids or phenolics are present, and polyester and polypropylene are excluded where caustics are present, which is a constraint on the fibre rather than on the item number.

7. Inspection, and What Ends an Article's Service

The intervals do not vary with the row of the table: an inspection each day before use, periodic inspections at intervals no greater than twelve months, and additional inspections where service conditions warrant, judged on the frequency of use, the severity of the service, the nature of the lifts and the experience of the service life. The conditions that remove a sling from service immediately include acid or caustic burns, melting or charring, snags, punctures, tears or cuts, broken or worn stitching, and distortion of fittings. The class page, heavy duty round sling, covers where that leaves this family against the chain family, which can be repaired and re-tested where a synthetic article is retired.

8. What the Enquiry Has to Carry

9. Frequently Asked Questions

Contact

Send the six lines in section 8, and we will come back with the row of the table that matches them, or with the questions that are missing. Articles are batch tested, marked per hitch and supplied with a certificate that names the article.

• Telephone and WeChat — 18066002268

• E-mail — 702461526@qq.com

• Address — Lifute Industrial Park, Taizhou City, Jiangsu Province, China