Analysis and Laboratory Testing of Technical Injury Prevention Measures for Portable Combustion Chainsaws
Round 1
Reviewer 1 Report
Manuscript: "Analysis and Laboratory Testing of Technical Injury Prevention Measures in Portable Combustion Chainsaws". This work is an assessment of technical safety solutions for portable chainsaws, and in detail shows the critical issues for injury prevention. This work provides valuable, comprehensive information and guidelines for engineers/scientists, manufacturers, users and salespeople of chainsaws.
The manuscript is nicely structured and very well written; easy to follow and understand. The figures and tables are stylish. I have read through carefully and cannot find any errors, misprints or other flaws, the work seems skillfully performed. I suggest this manuscript to be accepted for publication with only (very) minor revision; the author could consider the following comment if relevant:
In some places (only a few), are the citations embedded to the text in a way that disrupts the "flow" when reading, for example: Line 183 "...in the publication [14]." Maybe it should be "... in a publication/work previously published [14]. The citation shouldn’t be a "word" in the sentence but a citing of what the sentence says. Line 275: In the figure and figure caption, the abbreviation N/A is used for "non-acceptable". It is easy to understand after reading in the figure caption, but the first thing most will see is "not-applicable/available". The N/A abbreviation is quite established to mean that. Could N/A be changed to something else?
Author Response
Point 1: In some places (only a few), are the citations embedded to the text in a way that disrupts the "flow" when reading, for example: Line 183 "...in the publication [14]." Maybe it should be "... in a publication/work previously published [14]. The citation shouldn’t be a "word" in the sentence but a citing of what the sentence says.
Response 1:
Action: In some places (line: 119, 124, 183 and 190), the positioning of citations in the text has been changed so as not to disrupt the "flow" when reading the paper.
Point 2: Line 275: In the figure and figure caption, the abbreviation N/A is used for "non-acceptable". It is easy to understand after reading in the figure caption, but the first thing most will see is "not-applicable/available". The N/A abbreviation is quite established to mean that. Could N/A be changed to something else?
Response 2:
Action: In the figure and figure caption, the abbreviation A and N/A were changed to Acc. and N/Acc.
Reviewer 2 Report
The paper deals with a significant issue of selected risks to workers working with a chainsaw. It can be said that this topic is very traditional and quite sophisticated, as it has been or is devoted to it for many decades by a number of researchers and practitioners. Therefore, there are quite a lot of results and knowledges concerning this issue that can be drawn while minimizing the risks of working with the chainsaw. This paper is a follow-up to the existing knowledges and is supplemented by some new ones. At the beginning of the paper, the danger of a chainsaw for a worker is correctly justified, eg by explaining the risk of cutting his body by a saw chain, highlighting the consequences of the so-called kickback, which is a typical phenomenon when working with a saw. The paper properly describes the solutions and methodology used, including the principles of instrumental laboratory tests. Here I would recommend to supplement the current pictorial material with a photograph of the test equipment used. The author states, among other things, that the tests carried out confirmed that some of the chainsaws used in Poland do not have the characteristics required by the relevant standard - it would be appropriate to indicate whether they were previously approved by an independent "third party", or not. To my knowledge, the essential means of countering the risk of kickback is the functionality of its chain safety brake, which should, according to the standard's requirements, brake the chain at full speed for a maximum of 0.1 seconds. What is the author's knowledge of this requirement? Did the author find a (positive) effect of the so-called safety modification of the saw chain on reducing the risk of kickback? Did the author find any new knowledge that would be fundamentally different from the current level of knowledge about the issue? On page 2 the author gives information about accidents in Poland when working with chainsaws. I would recommend here to state what reason (source, cause) these injuries have, ie whether they are caused by sawing saw (eg kickback) or whether the prevalence of injuries caused otherwise.
In conclusion of my review, I would like to emphasize that I consider the submitted paper to be of high quality, up-to-date, based on solid material and correct solution methodology, providing interesting and necessary information for the research sector, chainsaw manufacturers and chainsaw workers themselves. I recommend to publish the paper after minor modifications. I also recommend to check the text of the paper by English native speakers.
Author Response
Point 1: The paper properly describes the solutions and methodology used, including the principles of instrumental laboratory tests. Here I would recommend to supplement the current pictorial material with a photograph of the test equipment used.
Response 1:
Action: The basic stand for the kick-back tests has been presented - additional figure 4.
Point 2: The author states, among other things, that the tests carried out confirmed that some of the chainsaws used in Poland do not have the characteristics required by the relevant standard - it would be appropriate to indicate whether they were previously approved by an independent "third party", or not.
Response 2:
Action: The first sentence of the Conclusion was complemented by information on the participation of the notified body in the assessment of essential requirements of the tested chain saws.
Point 3: To my knowledge, the essential means of countering the risk of kickback is the functionality of its chain safety brake, which should, according to the standard's requirements, brake the chain at full speed for a maximum of 0.1 seconds. What is the author's knowledge of this requirement?
Response 3:
Comment: Chain saws are listed in Annex IV to directive 2006/42/CE. However, if this machine has been produced in accordance with the harmonised standards, it can be placed on the EU market without the participation of a third party (notified body). Then the basic reference document confirming compliance with the essential requirements is a declaration of conformity issued by the manufacturer. This document also makes a reference to the standard harmonised with the Machinery Directive, used to ensure compliance with the essential safety requirements.
In general, however, manufacturers of chainsaws placed on the Polish market use the participation of a notified body (due to the high risk caused by chainsaws).
In some of chain saws tested in our Institute there were nonconformities (tests commissioned mainly by market surveillance authorities operating in Poland). I believe that identified during the tests deficiencies arise mainly on the complicated and long path between the producer and the target sales market (many intermediaries are often on this path). In accordance with harmonised standards: 1) the computed kick-back angle/chain stop angle shall not exceed 45⁰; 2) the average stopping time shall not exceed 0,12 s and the maximum stopping time shall not exceed 0,15. In our tests of new chain saws, there were no non-conformity of these two parameters. Nevertheless, the risk of injury caused by the use of chainsaws is influenced not only by the design features of the machines but also by their proper use (e.g. use of chainsaws for professional or non-professional work, selection of saw chains and guide bars, technical condition of the chain saw).
Point 4: Did the author find a (positive) effect of the so-called safety modification of the saw chain on reducing the risk of kickback?
Response 4:
Comment: Safety modification of the saw chain on reducing the risk of kickback was described in previously published manuscripts [14,16]. Undoubtedly, the positive effect of these research is conclusion that the proper selection of the parameters of the chain and guide bar can reduce the risk of kickback. The spread of kickback angles can be seen in Figure 10, which shows how much depends also on the user, who has an influence on the choice of technical parameters of saw chain (inclination angle of cutting edges, lowering of depth gauge, blunting of cutting blades) and guide bars (length and type of tips) according to the manufacturer's recommendations and others parameters of the machine.
Technical progress in this area has made it possible to select the technical parameters of the chain saw so that the user can maintain safety according to their skills and working conditions.
Action: The similar summary (last sentence) has been added at the end of the text in the chapter Conclusions.
Point 5:Did the author find any new knowledge that would be fundamentally different from the current level of knowledge about the issue?
Response 5:
Comment: The paper presents a complete analysis of the safety of using chain saws, taking into account all parameters (elements) of machines affecting this safety, using the results of research [14,16] and those made after the publication of the mentioned articles.
Previously performed research (referred also to in this paper) and described in [14.16] led to a number of interesting new conclusions in the context of kickback phenomenon concerning eg.: chisel chains, which are best for professionals because they ensure high technological efficiency and decreased kickback angle, tracking the movement of the saw chain links on the guide bar during kickback using a high-speed camera and kickback angle during cutting wood of different properties. But in some of chain saws tested in the our Institute there were nonconformities concerning mainly the operation of the inertia brake activation mechanism (it's also an additional kickback protection), geometric dimensions of the front guard, strength of the front handle, chain catcher and control elements (tests commissioned mainly by market surveillance authorities operating in Poland). The compliance of these parameters with the standard also has the additional effect of reducing the risk of contact with the saw chain (such as properly saw chain stopping time and kickback reducing). This is not always properly noticed by saw manufacturers and users. The view on these irregularities that can sometimes be easily identified and can protect the chain saw user from unnecessary risk
Action: The supplemented text is inserted at the beginning of the Conclusions “Testing on portable combustion chainsaws (with a declaration of conformity relating to the involvement of the notified body in the assessment of conformity with the essential requirements) has identified non-compliances in some of these machines available on the Polish market concerning the operation of the inertia brake activation mechanism (it's also a additional kickback protection), geometric dimensions of the front guard, strength of the front handle, chain catcher and control elements.Compliance of these parameters with the standard also has the additional effect of reducing the risk of contact with the saw chain, such as appropriate saw chain stopping time and kickback angle reducing. This is not always properly noticed by chain saws manufacturers and users”.
Point 6: On page 2 the author gives information about accidents in Poland when working with chainsaws. I would recommend here to state what reason (source, cause) these injuries have, ie whether they are caused by sawing saw (eg. kickback) or whether the prevalence of injuries caused otherwise.
Response 6:
Action: KRUS data shows that half of the accidents at work with chainsaws were caused by contact with a moving saw chain - this information is given in addition on page 2.
Point 7: I also recommend to check the text of the paper by English native speakers.
Response 7:
Action: Current revised and supplemented version of the paper has been checked by MDPI English native speakers.
