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Britmarine
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National Standards for Basic Gear: Snorkels

Sun Nov 30, 2014 7:14 am

Right, on to the second item of diving headgear. I shall dedicate this thread to three Standards (British, German and European) with specifications for snorkels, attempting once again to determine what they all have in common and what sets each of them apart. In this first message of the thread I return to British Standard 4532:
Image
1. British Standards Institution (December 1969) BS 4532. Specification for snorkels and face masks. London: British Standards Institution. This British Standard, which was amended on 30 December 1977 and whose status remains "current", is 11 pages in length and available for purchase from http://shop.bsigroup.com/ProductDetail/ ... 0000132783

Foreword: According to this section preceding the specification proper, "a snorkel allows (the wearer) to breathe without having to raise the mouth out of the water whilst swimming, or floating face downward with nose and mouth submerged." Snorkels used both by the "untrained or casual skin diver" and by the "fully equipped free diver" are covered.
Snorkel_General.jpg
Scope: The Standard specifies requirements for "snorkels (...) used for recreational purposes."

General: This section defines and dimensions the snorkel:
Snorkel_General.jpg
Materials and design: This section elaborates on what is written in the preceding section, specifying the characteristics of the mouthpiece orifice and lugs, the tube, the mask attachment loop and any shut-off valve fitted. Tubes with an internal diameter greater than 20 mm are declared unsuitable for children:
Snorkel_Mat&Des.jpg
Instructions: The Standard requires a warning label to be affixed to the tubes of all snorkels and a set of instructions to be enclosed with each snorkel. I have posted below the BS4532-prescribed "safety notes" enclosed with a Britmarine snorkel I have in my collection, made by the former underwater gear manufacturer Haffenden-Richborough of Sandwich in Kent in the south-east of England:
Image

Marking: The Standard requires compliant snorkels to be marked with this British Standard's number and the manufacturer's name. Snorkels whose internal dimensions rendered them unsuitable for children had to be marked accordingly:
Snorkel_Marking.jpg
Appendices: Appendix A describes a "test for rigidity of tube":
Snorkel_Appendix.jpg
So those are the implications of BS4532:1969 for snorkels. I'll finish with a scan of the snorkels page from a 1970s Haffenden-Richborough underwater catalogue referring to BS4532 compliance:
Britmarine_Snorkels.jpg
In case the BS4532-related wording on the page isn't clear, here's a blow-up:
Britmarine_BS4532-2.jpg
Can you work out why the snorkel with the designation B.33 Mariner is non-compliant? It's because it has a soft, flexible, corrugated portion between the mouthpiece and the tube proper, allowing the mouthpiece to hang down vertically and out of the way when the snorkel is not in use. Such an arrangement would cause the snorkel to fail the snorkel rigidity test when applied to the "curve of the tube". Such "concertina" snorkel designs are much rarer nowadays, but there is still one around, the "Seac Corrugated Old Style Snorkel":
Image
However, the snorkel's mouthpiece and collapsible corrugated bend are both made from EPDM rather than natural rubber.

I hope this posting has been of some interest. In my next posting to this thread I shall be taking a look at the German Standard for snorkels, DIN7878 of February 1980.
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Britmarine
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Re: National Standards for Basic Gear: Snorkels

Sun Dec 07, 2014 6:45 am

Let's move on to the German Standard for snorkels, DIN7878:

2. Deutsche Institut für Normung (February 1980) DIN 7878. Tauch-Zubehör: Schnorchel. Maße. Anforderungen. Prüfung. Berlin/Cologne: Beuth Verlag. Available for purchase from http://www.beuth.de/en/standard/din-7878/2098894

This German Standard, subtitled with the official English translation "Diving accessories for skin divers; snorkel; technical requirements of safety, testing", is no longer in force and just 2 pages in length.

Scope and Purpose: The Standard is designed to cover snorkels intended to enable swimmers and divers to breathe when face down on the surface of the water. The object is to lay down minimum safety requirements to improve diver safety.

Normative references: Another German Standard, DIN 4844 Part 2, relating to safety markings and safety colours.

Concepts: The volume of the device involved in "pendulum breathing" is defined as "Dead Space T."

Dimensions and nomenclature: The Standard provides an illustration to clarify the naming of parts with the proviso that not all snorkels will resemble the image. There is also a table mandating the dimensions for the inner bore of Form A (child) and Form B (adult) snorkels:
DIN7878b.jpg
For the non-German-speakers, here's a vocabulary list: Schnorchel-Innendurchmesser = snorkel internal diameter; Schnorchellänge = snorkel length; Sicherheitsfarbstreifen = safety colour banding; Haltevorrichtung = keeper; Teleskopeinrichtung = telescopic device; Rohr = tube; Totraum T = dead space T; Kinder = children; Erwachsene = adults; bis = to.

There follows a longish section devoted to safety requirements:
Material: The mouthpiece must be in accordance with German foodstuffs legislation.
Keeper: Snorkel must have a keeper that will not separate from the snorkel.
Mouthpiece: Must be anatomically shaped, all edges rounded to a radius of at least 1 mm.
Dead space: In Form A (child) snorkels a maximum of 120 cm³, in Form B (adult) snorkels, a maximum of 150 cm³.
Safety colour banding: At the supply end of the snorkel there must be safety colour banding at least 30 mm wide in fluorescent orange-red. Safety colour banding made from PVC appears to be long lasting.

Next comes another longish section, dedicated to testing each of the above.
Material: Manufacturer's declaration.
Keeper: A pulling force of 20 N will be used to test the keeper's tensile strength. In the process, the keeper must not detach from the tube.
Mouthpiece: The anatomic design of the mouthpiece will be assessed by visual inspection and by measurement of the radius of the edges.
Dead space: Tested by measurement.
Safety colour banding: Tested by measurement. Colour tested by comparison with the RAL colour standard.

Marking: The Standard required any snorkels complying with its specifications to be marked with the name or symbol of the manufacturer, distributor or importer, alongside the number of the Standard (DIN 7878) and the user category (A or B). Here is a real-life example from an ad for adult snorkels (hence DIN 7878B):
DIN7878c.jpg
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Britmarine
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Re: National Standards for Basic Gear: Snorkels

Sun Dec 14, 2014 7:39 am

On to the European Standard for snorkels. I should explain to readers outside Europe that European Standards are adopted by member countries using the same European Standard number with the specification in one of three official languages (English, French and German). I'll focus on the version adopted by the United Kingdom:
BS_EN_1972_1997_1.jpg
3. British Standards Institution (15 November 1997) BS EN 1972. Diving accessories. Snorkels. Safety requirements and test methods. London: British Standards Institution. This British Standard, which was amended on 30 December 1977 and whose status remains "current", is 11 pages in length and available for purchase from http://shop.bsigroup.com/ProductDetail/ ... 0001208124

This European Standard is 8 pages in length and remains in force today, although a new version is under development which has not reached the public comment stage yet.

Introduction: The opening paragraph reveals why the Standard is necessary: "A snorkel allows the user to breathe when facing downwards without having to raise the mouth out of the water. However, using a snorkel complicates the greathing process." There follows an explanation of the problematical nature of snorkel use, including dead space, breathing resistance and the possibility of accidents.

Scope: The object is to lay down minimum safety requirements to improve the safety of swimmers as well as skin and SCUBA divers when using snorkels. Combined face masks and snorkels are exclided from the specification.

Normative references: The Standard incorporates provisions from other publications, more particularly ones relating to toy safety, hardness of plastics and lighting.

Definitions: A snorkel is defined as "A device composed of a tube with a mouthpiece and such optional devices as valves, water deflectors, allowing breathing while swimming in a face-down position." A mouthpiece is defined as "That part of the snorkel which is inserted between lips and teeth and which comes into contact with the mucous membrane of the mouth during correct use."

There follows a longish section devoted to safety requirements:
Dimensions: The dimensions of the snorkel, illustrated in Figure 1, must comply with Table 1:
BS_EN_1972_1997_5a.jpg
BS_EN_1972_1997_6b.jpg
Mouthpiece: Requires that the mouthpiece be made of non-toxic material (e.g. rubber, silicon, vinyl), that the material should comply with rules on element migration from polumers, that it should be designed to be easily retained in the mouth, that the hardness should not exceed 80 Shore A, that the design should not compromise its nominal cross-section during use, that all parts should be smoothly finished and that the end of the tube should not extend beyond the mouthpiece.
Tube: A maximum hardness of 100 Shore A.
Flow of air: Sets limits to the snorkel's resistance to flow of air.
Joints: No sign of disengagement when subjected to force.
Optional devices: Adjustability of snorkel keeping device. Shut-off valves should only shut off when submerged. No sharp edges. Top of the tube to be marked in fluoresecent red to yellow or pink.

Another longish section follows, devoted to test methods:
Testing of dimensions: Length 1 to be determined as the distance between the centre of the mouthpiece opening and the lowest part of the air intake opening.
Method for determination of the air flow: Mouthpiece to be connected to a breathing simulator set to a sinusoidal operation of 25 strokes/min.
Method for the determination of strength of joints: Joint subjected to tensile force, then examined for damage. Clamps to be attached on either side of the joint and a force of 50 N to be applied over 5 s.

Warning label: "For your safety read the enclosed instructions."

Instructions for use: Snorkel only to be used in water. Possible misuse, e.g. size 2 snorkels not to be used by persons < 150 cm. No foreign objects to be added, e.g. extending length. Depth limitation if any. Sie grouping. Maintenace and storage instructions, imcluding replacement of safety colour marking.

Marking: Name, tradmark of manufacturer, supplier or importer. Number of European Standard EN 1972.

Here is a real-life example from ads for Type 1 EN 1972 children's snorkels and Type 2 EN 1972 adult snorkels (hence EN1972 Type 2):
EN1972-1.jpg
EN1972-2.jpg
And just in case these snorkels are too modern for your taste, here are a few old-school ones still produced by Sommap of France:
Sommap.jpg
I'll leave you to work out whether they comply with EN 1972 or not! And the following Greece-manufactured retro combined snorkel masks definitely don't conform:
Balco
Image
Majorca sub
Image
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couv
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Re: National Standards for Basic Gear: Snorkels

Sun Dec 14, 2014 10:06 am

Thank you David. The last 2 remind me of a movie I saw years ago.
https://www.google.com/url?sa=t&rct=j&q ... 8268,d.eXY
A sincere THANK YOU to all at VDH who make this wonderful resource available and to all the thoughtful contributors.

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Britmarine
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Re: National Standards for Basic Gear: Snorkels

Sun Dec 14, 2014 12:28 pm

couv wrote:Thank you David. The last 2 remind me of a movie I saw years ago.
https://www.google.com/url?sa=t&rct=j&q ... 8268,d.eXY
Thank you for the acknowledgement. And they certainly don't make films like that any more, whether it's the use of a combined snorkel mask as a prop (what are those tubes doing attached to the supply end of the snorkels?) or that actress's tortured English aristocrat vowels!

David

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Britmarine
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Re: National Standards for Basic Gear: Snorkels

Sun Dec 21, 2014 6:35 am

Comparison time and once again there is considerable overlap among these standards when it comes to snorkels. All, for example, limit the size of the internal diameter in general and set defined limits when it comes to snorkels suitable for children. For this purpose the German standard has two categories, A and B, for children and adults respectively, while the European standard divides users by height, those 150 cm or less and those taller than 150 cm. Other safety considerations dominate too, such as the use of a brightly coloured band around the top of the snorkel that will alert other water users of the snorkeller's presence.

Finally, and I mean "finally" as far as this topic is concerned, there are two French-language files providing functional analyses of snorkels from an educational perspective:
1. Ministère de l’Education Nationale (1994) Matériels et équipements pour la pratique des activités physiques et sportives des adolescents et des jeunes. Collèges et lycées. Matériel aquatique. Tubas. Focuses on snorkel use by teenagers. See the PDF file freely downloadable from http://www.economie.gouv.fr/files/direc ... ifs/53.pdf
2. Girault, R. and Adele, F. (2007) Analyse fonctionnelle tubas. Focuses on snorkel use with no particular target population in mind. Free download of Excel file from http://www.optimisations.fr/stats/OP_P& ... bas%20.xls
For those who read the language, these files are an interesting illustration of the way French schools teach the subject of product design.

For my next project, I am minded to review the literary history of national and international Standards for dry suits. The thread would follow similar lines to the present one. I hope this would be of interest to Bibliophile Forum visitors :D. All the documents are ready!

In the meantime, please feel free to voice your opinion, or even better, to start a thread of your own here with a review of your favourite item of vintage diving literature. And compliments of the season to everyone! Normal service will return in a little over a week's time when I come back online.

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