{"id":987474986,"date":"2024-09-12T14:30:58","date_gmt":"2024-09-12T14:30:58","guid":{"rendered":"https:\/\/courses.asiascubainstructors.com\/lessons\/physics-4-the-ear-copy\/"},"modified":"2025-06-06T02:47:06","modified_gmt":"2025-06-06T02:47:06","slug":"equipment-1-scuba-cylinders","status":"publish","type":"lessons","link":"https:\/\/courses.asiascubainstructors.com\/de\/lessons\/equipment-1-scuba-cylinders\/","title":{"rendered":"Restricted content"},"content":{"rendered":"

[et_pb_section fb_built=”1″ admin_label=”Classes Section” _builder_version=”4.23.1″ _module_preset=”add7fec1-62f1-4656-9396-e46e61dbc3b7″ background_color=”RGBA(255,255,255,0)” custom_margin=”||||false|false” custom_padding=”0px||||false|false” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_row use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_color=”#4E70C9″ background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”3%|3%|3%|3%|true|true” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”8b1f8231-1210-4c64-bae4-d177be5c655c” text_text_color=”#FFFFFF” header_2_text_color=”#FFFFFF” header_3_text_color=”#FFFFFF” header_4_text_color=”#FFFFFF” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

Equipment<\/h1>\n

 <\/p>\n

1. Scuba Cylinders<\/h2>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”10%||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_phone=”|5%||5%” custom_padding_last_edited=”off|desktop” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

Scuba cylinders<\/h3>\n

Most scuba cylinders are made from aluminium or steel. Tanks can be made from other materials like titanium or fiber composites but they have very limited use in recreational diving.<\/p>\n

Steel cylinders<\/strong><\/em> are negatively buoyant, even when empty. This means you need to carry less weight on your weightbelt. They can have a higher capacity (working pressure) than aluminium tanks. The primary disadvantage of steel cylindersis that they can rust easily.
Aluminum<\/em><\/strong> is a softer metal than steel, so the walls of an aluminum cylinder must be thicker. This makes these cylinders larger and heavier. However, empty aluminium cylinders are positively buoyant in the water. Aluminum corrodes just as steel but the aluminum oxide adheres to the metal, creating a barrier that inhibits further corrosion.<\/p>\n

<\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”3_5,2_5″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”3_5″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_phone=”|||” custom_padding_last_edited=”off|desktop” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.16″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” custom_padding=”||5%|” global_colors_info=”{}” theme_builder_area=”post_content”]All scuba cylinders have markings<\/strong><\/em> stamped on the top. Markings always include:
\n– The metal type
\n– Hydrostatic test date
\n– Working pressure
\n– Manufacturer\u2019s name
\n – Serial number<\/p>\n

Cylinders can have additional markings depending on the country where the tank was made:
\n– Thread Specification
\n– Empty weight
\n– Test pressure
\n– Regulatory authority, (for example U.S. Department of Transportation – DOT)
\n– Visual inspection sticker[\/et_pb_text][\/et_pb_column][et_pb_column type=”2_5″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|0px||5%” custom_padding_tablet=”” custom_padding_phone=”10%|||0px” custom_padding_last_edited=”on|phone” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_image src=”https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/PADI-IDC-theory-scubatanks-all_colors.jpg” force_fullwidth=”on” align_tablet=”center” align_phone=”” align_last_edited=”on|desktop” _builder_version=”4.16″ _module_preset=”default” animation_style=”fade” animation_delay=”500ms” global_colors_info=”{}” theme_builder_area=”post_content”]   [\/et_pb_image][\/et_pb_column][\/et_pb_row][et_pb_row use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_phone=”|5%||5%” custom_padding_last_edited=”off|desktop” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

Tank valves<\/h3>\n

K-valve<\/strong><\/em>: This is a simple on off valve. Almost all modern scuba tanks have a K valve.
J-valve<\/strong>:<\/strong><\/em> This valve closes the airflow when the tank pressure is low (20-40 bar). The diver needs to pull a lever to re-open the airflow. J-valves were used before the invention of submergable pressure gauges (SPG) and it is very unlikely to see it in modern scuba equipment.<\/p>\n

On a tank with an\u00a0INT valve<\/strong><\/em>, the regulators\u2019 first stage is clamped on the valve. The o-ring is in the tank valve. INT (international) valves are often called Yoke valve.
With a DIN valve <\/strong><\/em>(Deutsche Industrie Norm), the regulator first stage is screwed into the tank valve.
It has less chance on small leaks and can hold higher pressure (up to 300 bar).
For this reason it is preferred by technical divers.<\/p>\n

Adapters<\/strong><\/em> can be used to fit a DIN regulator on a Yoke valve and vice versa.<\/p>\n

Most modern cylinders valves have a burst disk<\/strong><\/em> that protects the cylinder against damage from accidental overfilling. When the tankpressure becomes too high (over 140%), the burst disk will rupture and pressure will be released.\u00a0<\/span><\/p>\n

<\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”1_3,1_3,1_3″ use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” module_class=” et_pb_row_fullwidth” _builder_version=”4.16″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”50px|0px|0px|0px|false|false” make_fullwidth=”on” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”1_3″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_image src=”https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/PADI-IDC-theory-k-valve-yoke-burstdisk.jpg” align_tablet=”center” align_phone=”” align_last_edited=”on|desktop” _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_image][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” text_font=”||||||||” background_color=”RGBA(255,255,255,0)” custom_margin=”10px|5%||5%” custom_padding=”10px||” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

K-Valve with INT connection and burst disk<\/p>\n

[\/et_pb_text][\/et_pb_column][et_pb_column type=”1_3″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_image src=”https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/PADI-IDC-theory-DIN-valve.jpg” align_tablet=”center” align_phone=”” align_last_edited=”on|desktop” _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_image][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” text_font=”||||||||” background_color=”RGBA(255,255,255,0)” custom_margin=”10px|5%||5%” custom_padding=”10px||” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

K-Valve with DIN connection and adapter<\/p>\n

[\/et_pb_text][\/et_pb_column][et_pb_column type=”1_3″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|||” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_image src=”https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/PADI-IDC-theory-J-valve.jpg” align_tablet=”center” align_phone=”” align_last_edited=”on|desktop” _builder_version=”4.16″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][\/et_pb_image][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” text_font=”||||||||” background_color=”RGBA(255,255,255,0)” custom_margin=”10px|5%||5%” custom_padding=”10px||” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

J-Valve\u00a0<\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”5%||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

Cylinder testing<\/h3>\n

As an industry standard, a visual inspection<\/strong><\/em> of the scuba cylinder should be done every year.
The cylinder (outside and inside) is examined for damage and corrosion, the valve is removed and serviced and the threads checked for corrosion and damage.<\/p>\n

Hydrostatic testing<\/em><\/strong> (pressure test) should be done out every 5 years, unless local regulations are different. If the cylinder is sanded to remove corrosion, if it suffered from impact or if it has been exposed to extreme heat, may also be a reason to carry out a Hydrostatic test.<\/p>\n

<\/span><\/p>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row column_structure=”3_5,2_5″ make_equal=”on” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”3_5″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_phone=”|||” custom_padding_last_edited=”off|desktop” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.16″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” custom_padding=”||5%|” global_colors_info=”{}” theme_builder_area=”post_content”]The cylinder is immersed in water and pressurized. The cylinder is NOT filled with air but also with water.  The test pressure is normally about 5\/3 of the working pressure. The cylinder will stretch slightly as it is pressurized. <\/p>\n

Next the pressure is released and the tester measures the cylinders permanent deformation. The permanent deformation of the cylinder should be within limits.<\/p>\n

If the cylinder fails during the test it will not explode as it is filled with water.[\/et_pb_text][\/et_pb_column][et_pb_column type=”2_5″ _builder_version=”4.16″ _module_preset=”default” custom_padding=”|0px||5%” custom_padding_tablet=”” custom_padding_phone=”10%|||0px” custom_padding_last_edited=”on|phone” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_image src=”https:\/\/courses.asiascubainstructors.com\/wp-content\/uploads\/2024\/09\/PADI-IDC-theory-hydrostatic-testsystem.jpg” force_fullwidth=”on” align_tablet=”center” align_phone=”” align_last_edited=”on|desktop” _builder_version=”4.16″ _module_preset=”default” animation_style=”fade” animation_delay=”500ms” global_colors_info=”{}” theme_builder_area=”post_content”]   [\/et_pb_image][\/et_pb_column][\/et_pb_row][et_pb_row use_custom_gutter=”on” gutter_width=”1″ make_equal=”on” admin_label=”Class Details Area” _builder_version=”4.22.0″ _module_preset=”default” background_size=”initial” background_position=”top_left” background_repeat=”repeat” max_width=”100%” module_alignment=”center” custom_padding=”||||false|false” use_custom_width=”on” width_unit=”off” custom_width_percent=”100%” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” custom_padding=”||||false|false” custom_padding_phone=”|5%||5%” custom_padding_last_edited=”off|desktop” global_colors_info=”{}” custom_padding__hover=”|||” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”fd3255d4-f6f0-4f87-9821-9341db4eea8f” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n

<\/span>Enriched air equipment considerations<\/h3>\n

Tanks that are used for Enriched Air \u2013 Nitrox normally have a yellow and green band around the cylinder that reads NITROX, or ENRICHED AIR.
The markings are not used everywhere because local laws may require different markings.
The cylinder must also have a contents sticker identifying the oxygen percentage, fill date, maximum operating depth and the diver\u2019s name.<\/p>\n

Modern tanks, valves, regulators and other equipment can be used with Enriched Air blends up to 40%. When using breathing gas that contains more than 40% oxygen, the equipment needs to be \u2018oxygen clean\u2019<\/strong><\/em>. The primary concern is the risk of cause a fire or explosion.<\/p>\n

 <\/p>\n

 <\/p>\n

<\/h6>\n

[\/et_pb_text][\/et_pb_column][\/et_pb_row][et_pb_row _builder_version=”4.22.0″ _module_preset=”default” locked=”off” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_column type=”4_4″ _builder_version=”4.22.0″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”][et_pb_text _builder_version=”4.22.0″ _module_preset=”default” global_colors_info=”{}” theme_builder_area=”post_content”]<\/p>\n