Why a Full Face Mask? page 3. The Full Face Mask page 5. Chapter 2 The Air Delivery System page 10. Diving with the Full Face Mask page 20

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2 Index Introduction Why a Full Face Mask? page 3 Chapter 1 The Full Face Mask page 5 Chapter 2 The Air Delivery System page 10 Chapter 3 Diving with the Full Face Mask page 20 Chapter 4 Problem Solving page 27 Chapter 5 Underwater Communication page 33 Chapter 6 Underwater Communicators page 41 Rel 5.0 OCEANREEF September 2010

3 Introduction Why a full face mask? Until a few years ago the full face mask was used only by professional divers and the military, but now it is employed by a large group of recreational divers who have adopted it as a useful accessory. In use in diving since the 1950s, the full face mask has undergone numerous modifications by its various manufacturers in order to satisfy the market s increasing requirements for comfort and performance. The major obstacle to the spreading of the mask s popularity was its high cost and difficult use. But modern technology and materials have made the full face mask economically accessible and, with proper training, easy to use. Excluding masks used predominantly by professionals, those made for recreational use were actually nothing but traditional masks with a downward extension to cover the face with black rubber or silicon and with a receptacle in front for attaching the regulator. Therefore, the transparent part allowing for vision was limited to the glass of a traditional underwater mask. Nowadays, modern full face masks tend to provide a greater field of vision by dedicating more area to the visor with relatively rigid support structures, differing pressure equalization systems, the possibility of adapting underwater communication systems and in some models, two regulators simultaneously, all with the advantage of increasing the user s safety and comfort. During winter months and/or while diving in cold water, we use dry suits to protect ourselves from the cold, thus keeping the body warm and dry with the exception of the hands and face. The use of thick or watertight gloves allows us to eliminate another source of heat dispersion. Even for those using watertight wetsuits, diving in cold water, and in lakes and rivers in particular, has always caused numbness of facial skin and sometimes sinus pain due to the low water temperature. Warm, wrap-around hoods haven t completely solved the problem because the limited volume of traditional underwater masks doesn t offer the face complete protection from the water. To protect the face from cold water there is no remedy other than using a professional diving helmet or a full face mask. Excluding helmets and full face masks created for professional use, due to their cost and difficult use, we ll turn our attention to masks created specifically for recreational divers. In this course we will present and evaluate the characteristics inherent in this type of mask, which is destined to be used by a growing number of divers in the next few years. Rel 5.0 OCEANREEF September 2010

4 Chapter 1 The Full Face Mask Factors in making a choice After deciding to use a full face mask, we must choose the one that best meets our requirements. In choosing from the various models available on the market, we should keep certain factors in mind: Features: Does it offer a broad field of vision, easy pressure equalization, the possibility of attaching two regulators and underwater communication systems, is it easy to put on quickly and take off in the water, is air re-circulated inside to eliminate condensation which tends to form? Adaptability: Does the mask adapt to the shape of all faces for a perfect, watertight fit? Corrective lenses: Does the mask offer the possibility of using glasses or installing prescription optics to correct sight defects? Instruction booklet: Is the purchased mask accompanied by a booklet explaining its features, use and maintenance? Easy maintenance: Is it possible to carry out one s own maintenance and repairs or is it necessary to send the mask back to the manufacturer? Reliability: Do you know about the manufacturer s experience in developing and producing this mask? What is the product s reputation in terms of protection, ease of use and reliability? Cost: The purchase of a full face mask is considerably more expensive than a traditional mask. Weighing the obvious use advantages and the possibility of adapting underwater communicators, you will realize the investment is not really so excessive. Materials used in the full face mask The materials used in the production of full face masks and their technical characteristics will influence your choice more than any other factor. For this reason it is necessary for you to understand these characteristics well before choosing which mask to buy. Caoutchouc (India rubber) Rubber/plastic/Lexan Rubber/plastic/glass Silicon Silicon/graphite Silicon/polycarbonate The first full face masks to appear on the market made of rubber or caoutchouc, were clearly of military origin. At first, these models were used with closed circuit oxygen scuba equipment. Later on experimental models like Galeazzi s VISIONAIRE, LOOSCO by Rel 5.0 OCEANREEF September 2010

5 G.L. Loos & Co. s Fabrieken N.V. were adapted for open circuit compressed air scuba equipment. The design of Visionaire was exceptional for its time. The mask constituted a fullfledged second stage whose glass visor took the place of the diaphragm, with manual pressure on the visor creating second stage pressure. All of these models were made of black rubber or caoutchouc (India rubber) and had large, flat visors for the face, with the exception of the models used by ARO which had a visor limited to the surface area of a traditional mask. The rest of the mask covered the face with black rubber and was contoured around the nose to allow for pressure equalization. A nose clip was necessary to carry out equalization with masks having large, flat visors. Following up on their military experience, underwater mask manufacturers first aimed at the professional market sector and then at the recreational diver with a series of highly sophisticated products which today make up a very attractive alternative to the traditional mask. The use of anallergic materials like graphite and silicon, plus face shields made of materials like lexan and polycarbonate which are more resistant than glass, have resulted in lower production costs, and therefore more widespread sales. Fastening system The full face mask is equipped with a series of straps or harness which converges in a junction at the back of the head. The straps (three or five according to the type of mask) leave the junction and are attached to points on the perimeter of the full face mask to guarantee correct positioning even in the event of accidental bumping. The straps of the harness must be long enough to allow the mask to be easily put on and worn over a thick hood for cold water diving. Adjusting the straps The straps are adjusted at the attachment points on the perimeter of the mask which are similar to those on a traditional mask. In this way it is possible to adjust the harness to achieve the desired tension. These fasteners must permit easy handling even while wearing gloves, so as not to create difficulty when correcting harness tension during a dive. A badly positioned adjustment system, or one with undersized straps, would not permit easy handling with thick gloves. When you are about to wear a full face mask you must Rel 5.0 OCEANREEF September 2010

6 remember to lengthen completely the harness straps to facilitate putting it on, be sure the pressure equalization system is correctly in front of the nostrils or make necessary adjustments and begin to tighten the straps in the correct sequence: 1. first the lateral straps 2. then the lower ones 3. and last the upper ones Once the straps are adjusted, the full face mask should adhere to the face like a traditional mask, without creating discomfort because it is too tight, or permitting the infiltration of water due to poor positioning. If the mask straps are not properly tightened, the air inside the mask will tend to escape from the upper edge, thus creating depression within the mask. In this situation the regulator may go into free flow, greatly increasing air consumption. The face shield The face shield is a very important part of the full face mask. As we have seen in the previous paragraphs, some full face masks are made of black opaque plastic material, with the transparent part, which permits vision, made of glass like a normal underwater mask. While it is true that this type of mask offers total protection of the face, the field of vision is exactly the same as a traditional mask. On a full face mask, where the face shield consists of a large transparent visor which is also structurally rigid, vision improves dramatically. The field of vision of the full face mask examined here is everything a scuba diver could possibly desire. The impression one gets when using it, is somewhat better than that offered by a good motorcycle helmet. Indeed, the horizontal field of vision is 120, and if you count the transparent contoured structure around the vision area you get to a full 180. This is significantly superior to similar models on the market and provides the diver with the quality of vision that he has always sought but seldom obtained. Among the various models produced, a few full face masks come with a protective shield. The purpose of the shield is to protect the visor of the mask from damage and abrasion when it is not being used in the water. This guarantees a longer life without scratches and maintains quality vision over time. Some models also offer the mask with a special resin treatment on the visor to make it more resistant to accidental impact and abrasion. Rel 5.0 OCEANREEF September 2010

7 Corrective lenses Unlike traditional masks, most full face masks don t allow for the use of corrective lenses. For those who have vision defects and would like to use a full face mask, we recommend trying the Neptune II NIRA produced by OCEAN REEF. This mask has among its accessories a glasses frame which fits into special guides located laterally, inside the mask skirt. This useful accessory, when fitted with lenses by your local optometrist, has the important advantage of letting you use your exact prescription for your corrective lenses. Therefore, you can use the same prescription you use on land, without having to accept a compromise, as is often the case with traditional masks for which all possible corrections do not exist. The watertight seal The seal of a full face mask must have a large area of contact with the face in order to guarantee a perfectly watertight fit. The rubber seal around the rim of a traditional mask is in contact with only about 2 cm. of the diver s face throughout the circumference of the mask. The contact surface of a full face mask is much greater. The various models cover as much as 4.5 cm. of the diver s face throughout the circumference to guarantee a perfect watertight fit even when the rim of the mask is covering the hood of a wetsuit, regardless of its thickness or material. Some models use molded seals in order to fit every type of face. In this way, it has become possible to adapt the full face mask to about 80% of all human faces. When buying this type of mask it is advisable to verify the perfect fit of the seal of the mask in question. Trying it on both with and without your wetsuit hood will give you a good idea of how well the mask adapts to your face. Like traditional masks made of transparent silicon, the seal of a full face mask will tend to turn yellow over time, making it look old. Therefore, it is advisable to choose a mask with a dark seal that will not appear to age over the years, even after countless dives. Rel 5.0 OCEANREEF September 2010

8 CHAPTER 1 - REVIEW 1. The first full face masks to appear on the market were made of or. 2. Visionaire was a mask that constituted a full-fledged, whose glass visor took the place of the. Manual pressure on it created. 3. The use of anallergic material like and, and visors made of transparent materials which are more resistant than glass like and have permitted the production of full face masks at lower, more accessible prices, thus allowing for more sales. 4. The full face mask is equipped with a series of which we will refer to as the which converges in a junction at the back of the head. 5. The straps of the harness must be enough to allow the mask to be easily put on and worn, even over a for cold water diving. 6. The fasteners must permit even while wearing gloves, so as not to create difficulty when harness tension during a dive. 7. When you are about to wear a full face mask you must remember to completely the harness straps to facilitate. 8. Begin to tighten the straps in the correct sequence: first the, then the, and last the. 9. If the mask are not properly tightened, the the mask will tend to escape from the upper edge, thus creating within the mask. 10. The face shield is a very part of the full face mask. 11. Among the various models produced, a few full face masks come with a. 12. The purpose of the shield is to the of the mask from and when it is not being used in the water. This guarantees a longer life without scratches and maintains over time. 13. The seal of a full face mask must have a of contact with the face in order to guarantee a fit. 14. Some models use seals in order to fit every type of face. In this way, it has become possible to adapt the full face mask to about of all human faces. Rel 5.0 OCEANREEF September 2010

9 Chapter 2 The Air Delivery System The regulator system Among the various models of full face mask on the market, there are different systems for attaching the regulator. Rubber masks have two systems for attaching the regulator. In one case you must take care to remove the regulator mouthpiece after cutting the plastic band, then reposition the mouthpiece inside the mask and attach a new plastic keeper band. In this way, when the mask is worn the mouthpiece is kept in the mouth in the usual manner. When you want to use the regulator with a traditional mask you need to carry out the operation in reverse. With the other system, once the regulator is attached to the mask without the mouthpiece inside, you can breathe either through the nose or the mouth like with a mask with a rigid visor. Certain masks have their own special regulator, often sold pre-assembled, and in this case no action is required. After attaching the regulator to the tank, the mask is ready to use. This solution is very practical; this is the case of NEPTUNE II NIRA Neptune II NIRA allows the regulator to be attached to a traditional standard (DIN) connector which takes the place of the mouthpiece. You start by removing the plastic band which fastens the mouthpiece to the second stage. Then, with another plastic band, you install the DIN connector instead of the mouthpiece. Thus, you attach the second stage of your regulator to the face shield of your mask by simply screwing in the new connector. Also with this solution you must remove the DIN connector and replace it with the traditional mouthpiece when you use the regulator with a traditional mask. The regulator Certain factors must be taken into consideration before choosing which regulator to use with a full face mask. Rel 5.0 OCEANREEF September 2010

10 No problems will be encountered in the choice of a regulator to be used with a rubber full face mask which allows for normal use of a mouthpiece because the system used is almost identical to the traditional system. For a full face mask where you breathe the air contained inside the mask, either through the nose or the mouth, instead of through a mouthpiece, we must take into account factors regarding: Regulator sensitivity A regulator which lacks sensitivity requires considerable effort to breathe, while one that is overly sensitive tends to go into free flow, creating discomfort for the diver. These two malfunctions could be influenced by the distance of the regulator from the mouth and by the position of the diver's head, and therefore of the second stage diaphragm, with respect to the seafloor or the surface. A wise choice would require the use of a regulator with a flow control valve to make it possible to increase or decrease required airflow depending on whether you are looking up or down, thus obtaining the most comfortable breathing at all times. Regulator position The position of the regulator on the full face mask, chosen by the manufacturer or the user, greatly influences the user's choice of a regulator. We have already mentioned the fact that looking down or up tends to increase or decrease the flow of air from the second stage if it is attached to the front of the mask. Both the distance of the second stage from the mouth and a diaphragm which faces towards the bottom tend to facilitate free flow and diver discomfort. In this position, if the harness straps are not positioned and tightened correctly, it is possible for the excess air in the mask to escape from the upper part of the mask skirt, thus causing depression inside the mask together with a bothersome leak which, in any case, can be halted immediately by looking horizontally or up. With better adjustment of the straps and turning the airflow control knob (on regulators which have one) you can overcome this inconvenience. This situation does not occur when the regulator is attached on the side of a full face mask. In this configuration the second stage diaphragm is always in a vertical, and therefore neutral, position unless the diver tilts his/her head to the side. But even in this case, since the regulator is not close to the mouth, its sensitivity will influence the ease of breathing. A correct adjustment of the flow control knob will provide comfortable breathing for the duration of the dive. The choice of a full face mask with frontal or lateral regulator ports, or one with its own special regulator, depends heavily on how the mask will be used and how much money you are willing to spend. Rel 5.0 OCEANREEF September 2010

11 Among the possibilities is a mask that allows for the use of two regulators simultaneously or the choice of attaching one either frontally or laterally. We will examine the possible advantages of having two regulators attached simultaneously later on in this booklet. Breathing in a full face mask One of the first things you will notice when you put on a full face mask and breathe for a while, is the total absence of jaw fatigue due to the lack of a mouthpiece to be held in position with the teeth. Breathing the air contained inside a full face mask is like breathing out of the water. Those who are more at ease breathing through the mouth can do so keeping the mouth open as much as desired, but the great novelty of this mask is the possibility of breathing through the nose like on land. Breathing with the mouth and the nose or just the nose When we started diving, we forgot how to breathe with the nose, and the first times we try a full face mask, though we know perfectly well that it is not necessary, we instinctively breathe with the mouth open. Sometimes we even push the chin downward against the lower rim of the mask, causing the jaw muscles to tire. Eventually we learn to open the mouth less and timidly try to inhale for the first time with the nose. Our first breaths are accompanied by the pleasant sensation of having our lungs full of air. We continue breathing with the nose and we realize there is a difference in the quantity of air we are breathing with respect to respiration through the mouth. After overcoming the perplexities of our first dives with a full face mask, it becomes evident that air consumption is reduced thanks to a more natural and relaxed way of breathing which is much closer to how we have always breathed. Air purity An important characteristic of a full face mask is the possibility of expelling exhaled carbon dioxide laden air and not re-breathing it inside the mask. Some full face mask models with the mouthpiece inside the mask, instead of allowing for inhaling and exhaling air through the nose, seriously limit the quantity of CO 2 rich air. Single chamber models, which permit free breathing with the nose and mouth, have only the visor between the face and the water. This creates high levels of carbon dioxide stagnation within the mask as exhaled air is not totally expelled from the mask and is therefore re-inhaled by the diver. Rel 5.0 OCEANREEF September 2010

12 Then there are the models with 2 separate chambers within the visor. We are referring to those masks which, within the greater volume of the visor, have a smaller pocket mask which we will call the oral-nasal pocket. The purpose of the oral-nasal pocket is to isolate the nose and mouth in a limited space dedicated only to breathing. Connected to the regulator port, it provides an influx of fresh air without allowing exhaled air to mix with the rest of the air inside the visor. In certain masks, the oral-nasal pocket, as well as the regulator, is connected to the exhaust valve of the full face mask. In this system the regulator's only function is to supply required air which, when exhaled, will flow out of the exhaust valve, generally located in the lower part of the oral-nasal pocket. Pressure equalization of the full face mask As depth increases, due to a well-known law of physics, the volume of air inside a traditional mask tends to decrease creating a bothersome suction cup effect that requires correction with the emission of air from the nose into the mask interior. Except for full face masks which call for the use of the regulator mouthpiece inside the mask, in which case you act as above, all other models equalize automatically with breathing. The air supplied by the regulator at existing pressure keeps internal mask pressure in balance with external pressure. Divers who habitually tighten their mask straps as much as possible and descend rapidly towards the bottom will discover the considerable advantages of this full face mask characteristic. Equalization There are several methods of carrying out pressure equalization, corresponding to the type of mask used. For masks made of soft material like rubber, silicon and graphite, equalization is carried out in the same way as with traditional masks. On all other masks with rigid face shields, since it is impossible for the diver to reach his/her nose with his/her hand to close the nostrils, equalization is performed differently. From the days of the earliest diving helmets to today, many systems of equalization have been used, the nose clip being the most functional, but somewhat uncomfortable. The adjustable equalization system inside the full face mask by OCEAN REEF. Today, the modern full face masks manufactured for recreational divers have a simple but ingenious system of equalization. Rel 5.0 OCEANREEF September 2010

13 Depending on the model, inside the oral-nasal pocket we find either a U-shaped rod or a pair of plugs made of anallergic material, usually soft silicon, positioned in front of the nostrils. When required, the diver presses on the visor of the mask, pushing the equalizing rod or plugs against his/her nostrils, thus blocking them. Generally the pressure equalization systems used on the various types of full face mask are adjustable so they can be adapted to the user's facial characteristics. The system should provide for modification of both the horizontal and vertical positions. We mustn't forget that full face masks are produced in just one size, so adjusting the straps and the equalization system are the only ways to personalize the mask. De-fogging the full face mask The first time user of a full face mask equipped with an oral-nasal pocket will be pleasantly surprised to discover that his/her vision through the visor is constantly clear. Gone are the problems of total or partial fogging due to the difference in temperature between the face and the external environment. To understand how this happens, it is necessary to examine the mask's ventilation system. The air to be breathed by the diver passes from the regulator to the mask interior. It is forced to flow along the inside of the visor before passing through two oneway valves in the oral-nasal pocket where it is available for respiration. Similar to the ventilation system of a car, which sends fresh air against the windshield with the air conditioning turned on, when we inhale we send fresh air from the tank across the entire visor, keeping it clear. During the exhaling phase, if our warm, humid breath came into contact with the visor it would immediately fog it up. Instead the exhaled air is forced out of the regulator's exhaust or, if so equipped, by way of the exhaust valve placed at the bottom of the mask. Under both systems, the air passes directly from the oral-nasal pocket to outside the mask without coming into contact with the visor, thanks to the one-way valves on the oral-nasal pocket. What could be the cause of mask fogging during a dive? Sometimes a diver may tighten the upper harness straps too much when putting the mask on, and as a result the mask is shifted upward together with the oral-nasal pocket. When this happens, besides the discomfort of having the equalization system too close to the nose and the sensation that the mask is dislodging from under the chin, the top of the oral-nasal pocket is pushed above its correct position. This results in the diver feeling the warm, moist air he has just exhaled escaping from the upper part of the oral-nasal pocket. It flows into his/her eyes and then fills the inside of the chamber enclosed by the visor. It doesn't take long for this air to cause fogging, creating considerable discomfort for the diver. An acceptable but drastic solution is to loosen the straps, let the mask fill with water, reposition it correctly and then drain the water. Rel 5.0 OCEANREEF September 2010

14 A better method, and certainly one more comfortable in cold water, is to slightly loosen the straps, move the mask downward until you feel the oral-nasal pocket in its correct position, properly tighten the straps and push the regulator purge button to let in fresh air and completely de-fog the visor. Obviously, while the above is valid for full face masks with an oral-nasal pocket, for less recent models the old system, using saliva or chemical solutions, is always possible, just as we used to do with traditional masks. The alternative is diving in the fog. Emptying a flooded full face mask During diving courses we often hear that in the water our diving partner can accidentally bump into us, moving our mask and causing it to flood or that water can get in where there are wrinkles caused by facial expressions, where the mask overlaps the wetsuit hood, where the mask covers hair, etc. But with the full face mask all this does not happen. The harness which, as we have seen, holds the mask firmly in place on the face with at least five fastening points, prevents any accidental movement of the mask, guaranteeing a watertight seal during the entire dive. The large surface area of the silicon skirt at the rim of the full face mask guarantees an exceptional watertight seal, even when it passes over the edge of the wetsuit's hood, whether it is made of latex or neoprene. Therefore, the flooding of a full face mask has become a rare event which is sought only for the purpose of learning how to empty it. Let's look at the sequence of operations to flood, take off and put back on the mask and then drain the water. Flooding the full face mask To flood the full face mask once it is put on and correctly adjusted, it is necessary to loosen the adjustable straps at the band where they attach to the rigid part of the mask to allow the diver to take the upper part of the mask in his/her hands and pull it away, separating it from his/her face and thus letting water in. In this way, just as with the partial or total flooding of a traditional mask, you can see how much water you have let in, and when the mask is flooded to the desired level you put it back on the face and prepare to drain the water. At this point, it makes no difference whether you choose to tighten the straps to their correct tension before or after draining the mask. Therefore, we'll choose to drain the mask before to reduce the possible discomfort that could result from having the face half covered by water. To do so, we simply push the regulator purge button. Rel 5.0 OCEANREEF September 2010

15 After the regulator purge button is pushed, the air forced into the mask will displace the water, pushing it towards the regulator exhaust or, if so equipped, towards the mask's exhaust valve which is usually located at the bottom of the mask. During this operation we should be aware of some potential complications. The water that entered from the upper edge of the mask could have covered the mouth, so remember to breathe slowly with the nose, since it is higher, to avoid inhaling water by way of the mouth. If you realize that the water level also covers the nostrils, to avoid carrying out the entire operation without breathing, briefly push the regulator purge button to evacuate a little water until you can relax and breathe comfortably. As soon as the water level inside is tolerable, position the mask correctly and then continue the evacuation procedure. Once the mask is drained, adjust the straps, remembering the correct position of the mask skirt with respect to the hood of the wetsuit. This operation requires some practice if done with gloves on. Removing the full face mask Taking off a full face mask is not at all difficult, and the time required is similar to that of a traditional mask. The only difference is that to take it off easily it is preferable to use two hands. From the time the lower straps are tightened so the mask adheres to the lower part of the face, it becomes difficult to remove the mask by simply pulling upward like with a traditional mask. The entire harness structure holds the mask firmly in place with several fastening points. Therefore, it is necessary to loosen the adjustable harness straps where they attach to the band which functions as the mask's rigid rim. Once the straps are loosened it is possible to take off the mask. There are different methods for putting on and removing the various types of full face mask. The possibility of rapidly carrying out these actions is one of the decisive factors in choosing which mask to use. One mask currently on the market uses pommels, easy to find even with gloves, attached to the mask's lower straps. Pulling outward and up allows the diver to remove Rel 5.0 OCEANREEF September 2010

16 the mask with one movement since pulling on the lower straps loosens the mask from the chin. This lets him easily remove the mask by rotating it upwards, using the central connection point of the harness as a hinge and without touching the other straps. With this system, when putting the mask back on, you only have to tighten the lower straps to have it correctly positioned because the other straps are already adjusted. The procedure is very quick, taking the same amount of time as required with a traditional mask. Naturally, with the mask off we have no means for seeing clearly or breathing. While we can still see well enough, it is very important to remember to continue exhaling air bubbles and not hold your breath. The first time you try this exercise, you may waste a little time adjusting the harness before passing it over your head to put the mask back on. Remembering that you normally cannot breathe during this time, it is nice to be able to relax and breathe from a regulator. Therefore, once the full face mask is removed, we should make contact with our alternative air source (AAS) and continue to breathe. This way we have time to learn to put the mask back on correctly and without haste. Putting on the full face mask underwater Putting on the full face mask while underwater is an operation that requires little practice to learn correctly. Remembering that we are breathing from our alternative air source, we can carry out the procedure calmly and correctly. The right sequence of movements Following the hose of the regulator connected to the full face mask, we grab hold of the mask and move our hands to the center of the lower rim (chin), turning the mask so that the visor faces down. We now have a good view of the mask interior and harness. Naturally, those having the regulator attached to the front of the mask will have to be careful to avoid provoking free flow when the second stage diaphragm is suddenly turned downward. Holding the lower rim with two hands and the thumbs inside, we slide the fingers up the respective sides of the mask until we have the straps of the harness gathered, the right strap in the right hand, and the left strap in the left. At this point, holding the straps in our hands, we can let go of the mask rim and put the mask on like we would a wetsuit hood, placing the head between the straps, making sure to remove the alternative air source from the mouth before placing the mask on the face. Once the mask is on, before tightening the straps, keep the visor pressed against the face with one hand and push the regulator purge button with the other, evacuating the water. When the water is eliminated from the mask, use the free hand to tighten the lower straps, completing the procedure. Rel 5.0 OCEANREEF September 2010

17 CHAPTER 2 - REVIEW 1. Among the various full face mask models on the market, there are different systems for the. 2. Certain masks have their regulator, often sold. 3. We have already mentioned the fact that looking down or up tends to or the flow of air from the second stage if it is attached to the of the mask. 4. Both the distance of the second stage from the and a diaphragm which faces towards the tend to facilitate and. 5. This situation does not occur when the regulator is attached on the side of a full face mask. In this configuration the second stage diaphragm is always in a vertical, and therefore position, unless the diver his/her head to the side. 6. In any case, regardless of position and the use of regulators with a, when necessary you can always increase the flow of air by pressing the regulator's second stage. 7. One of the first things you will notice when you put on a full face mask and breathe for a while, is the total absence of due to the lack of a mouthpiece to be held in position with the teeth. 8. An important characteristic of a full face mask is the possibility of expelling exhaled laden air and not it inside the mask. 9. The purpose of the is to isolate the and in a limited space dedicated only to breathing. Connected to the regulator port, it provides an influx of without allowing exhaled air to with the rest of the air inside the visor. 10. The air supplied by the regulator at keeps internal mask pressure in with external pressure, therefore no is necessary. 11. There are several of carrying out equalization, corresponding to the type of used. 12. Today, the modern full face masks manufactured for recreational divers, have a simple but ingenious system of. 13. Depending on the model, inside the oral-nasal pocket we find either a rod or a pair of made of anallergic material, usually soft. Rel 5.0 OCEANREEF September 2010

18 14. Generally the pressure equalization systems used on the various types of full face mask are so they can be to the diver's characteristics. 15. When we inhale we send fresh air from the tank across the entire, keeping it. 16. During the exhaling phase, if our, breath came into contact with the visor it would immediately. Instead the exhaled air is forced out of the or, if so equipped, by way of the placed at the bottom of the mask. Rel 5.0 OCEANREEF September 2010

19 Chapter 3 Diving With the Full Face Mask Preparing for a dive When you have gained sufficient confidence in your ability to assemble, adjust, drain and breathe in the mask, you are ready for our first dive. During this phase, your instructor will help you put on the full face mask according to the type of wetsuit you are using. Before putting the mask on, if you haven't already done so, you must remember to adjust the pressure equalization system. On full face masks with a rigid visor, it is impossible to touch your nostrils with your hands in order to perform the traditional equalization operation. Therefore, before diving we must make sure we can equalize the pressure in the sinuses and ears without difficulty, using the method required by the model we are wearing. When putting the mask on, make sure the oral-nasal pocket is correctly positioned so that the equalization device is exactly in front of the nostrils. If it is, by simply pressing on the visor, the silicon plugs will block the nostrils and permit equalization. After making sure we can properly carry out the equalization procedure, we can put on the mask as follows. When water temperature permits, either in a swimming pool or in the sea, simply put the full face mask on your bare head without any special considerations. The large surface area of contact between the mask skirt and the diver's face provides an excellent fit for almost all human faces with two mask sizes. When wearing the hood of a wetsuit or semi-dry suit, after correctly positioning the harness on the back of the head and pulling the mask down to cover the face, you must take care to pass the edge of the mask skirt under the hood like you do with a traditional mask. This should be done along the entire circumference of the face, including the cheeks and the chin. If using a dry suit and you want to keep your head warm and dry, and assuming the hood is attached to the dry suit, you put on the full face mask with the mask skirt resting on the exterior of the hood. Since the mask, along with the fins, is the last piece of diving equipment to be put on, at this point we can say we are ready to enter the water. If we are ready to enter the water long before our diving partner, breathing in the mask would result in unnecessary consumption of the air in our tank. To avoid this we can choose from the following: 1. Take off the mask and wait for our diving partner to finish getting ready, then put it back on. Rel 5.0 OCEANREEF September 2010

20 2. Loosen the lower straps enough to keep a finger or two between the chin and the mask to let in external air and breathe normally to avoid using the regulator. 3. On models equipped with a second port (for a 2 nd regulator or a communicator) we can remove its plug to let in fresh air and replace the plug just before entering the water. The second and third options can also be carried out in the water as long as we are careful to attach a safety line to the plugs and anchor them to the mask so we don't risk losing them. While waiting for our diving partner with our mask on, whether in a boat or in the water, it is possible to develop some light fogging inside a full face mask. This problem can easily be resolved when we tighten the lower straps or replace the regulator port plug. As the regulator comes into operation it will de-fog the visor. If this is too slow, we can always push the regulator purge button and the burst of forced air will immediately eliminate the inconvenience. Entering the water After making sure everyone is ready we can enter the water. Entering the water from the shore is the same as with a traditional mask and therefore no special suggestions are required here. When entering the water from a boat or a dock, where the diver makes a sudden impact in the water, with a traditional mask the diver is advised to protect the mask with a hand to avoid the mask being dislodged upon impact. This is not necessary with a full face mask because the multiple fastening points of the harness keep the mask in place, even on impact, so we can use both hands for holding such things as torches, underwater cameras, etc. This is true whether we roll backwards into the water from a boat or jump in feet first. Descending with the full face mask We are now ready to dive. After making the preliminary checks and giving the okay signal to our partner, we drift down along the guide line or along the bottom. During descent it is possible to assume the position in which we feel the most comfortable. Normally breathing is more regular with the head up and feet down. Descending with the head down can cause the regulator to go into free flow (if it is attached in front) and this is bothersome for the diver. At this moment the right adjustment of the regulator's flow valve sensitivity will produce easy breathing. It is difficult for us to understand how we managed to dive for so many years with a mask that limited our field of vision to such a great extent. Rel 5.0 OCEANREEF September 2010

21 The large visor of the full face mask offers us a new and unusual view of the world that we dive to admire. Just by moving our eyes, and without moving our head, we have a field of vision of about 180, depending on the model used. If we have correctly adjusted the pressure equalization system, we can now easily try to equalize. The operation is easier than it is with a traditional mask. Most divers feel they need to use two fingers to pinch the nostrils shut. By simply applying pressure on the upper edge of the mask the system presses against the nostrils and blocks the passage of air. This operation can be carried out even if your hands are full, applying pressure with your wrist or the back of your hand, just like when you drained a traditional mask. Don't insist if you encounter difficulty as you could fail to equalize and cause problems with your ears. You probably haven't correctly adjusted the equalization system. If this is the case, you should return to the surface and adjust it correctly. To observe his/her surroundings during a dive, a diver assumes different positions that can vary the amount of air delivered by the regulator, depending on whether he is looking up, down or even to the side. Learning to regulate the flow of air, making it more or less sensitive to pressure changes, helps us maintain a constant supply of air. Some regulators don't require further tinkering for the duration of the dive once the right balance has been found. After reaching the bottom in relatively shallow water, we should try to gain confidence with the mask by performing a few simple exercises. While standing on your feet or your knees, whichever you find more comfortable, lower your head to look at the bottom so that, if the regulator is attached frontally, you provoke free flow and take note of the intensity. Then, slowly raising your head to look at the surface, you should feel some difficulty breathing due to a slight lack of air. Repeating this exercise several times, trying to progressively reduce the angle down and up, will help you know how much you can raise or lower your head without encountering appreciable free flow or a lack of air, beyond which you would have to press the regulator's purge valve. Clearly, the above exercise pertains to those who have frontally attached regulators without flow control valves. For those using regulators with a flow control valve the exercise is purely academic. After this test, we'll try to adjust the air flow to find the right compromise between respiratory difficulty and free flow. It is important to learn to keep the face in the right position because every time you look down the regulator goes into free flow. Once you understand how to give the right sensitivity to the flow control valve you can look in all directions without having to continuously fine-tune the valve. After finding the right adjustment, we can move on to the next exercise which requires us to be in a perfectly stable horizontal position in the water with the face looking down as we try to get accustomed to the slow, steady flow from the regulator. In this position you will notice excess air from the mask seeping out from the mask's rim. For anyone wearing a wetsuit with a separate hood, it will not be difficult to maintain this position Rel 5.0 OCEANREEF September 2010

22 since the excess air will escape from the neck of the hood if the chin is pressed against the chest. Then, we roll over into the supine position, now looking towards the surface. If the setting of the regulator's valve is correct, we should be able to breathe without difficulty in this position. If not, the flow should be slightly increased so we can breathe without any appreciable effort. Naturally, the vertical position with the head up doesn't create any breathing problems since the diaphragm of the regulator is in perfect equilibrium with the surrounding pressure. The same can be said of the vertical position with the head down. An observation on the vertical, head-down position While a traditional regulator mouthpiece will give the impression of more difficult breathing in this position, a full face mask with a well adjusted regulator provides fluid breathing without significant effort. This exercise of the four basic positions is useful only to let you gain confidence with a full face mask with the regulator attached frontally, so that you can understand and control the various reactions of the regulator to the various situations. The situation changes completely if the frontally attached regulator is the lateral diaphragm type (Aga, Poseidon, and Oceanic). In this case the regulator's response in all four positions will be identical since the diaphragm is always in a position of equilibrium. Point the flow of air from the exhaust under the mask in the right direction to avoid having air bubbles in front of the mask. Pointing it laterally will force most exhaust bubbles to the side where they can't interfere with vision. Later we will also see the effect of these bubbles on the antenna of the communication system. Now we'll look at a full face mask with a side-mounted regulator. In this position any type of regulator, with or without a flow control valve, functions well since the second stage diaphragm is in a neutral position, regardless of the diver's position. Therefore, those who already own a regulator without a flow valve can choose to use a full face mask that takes a side-mounted regulator and avoid buying another regulator. Clearly, even if attached laterally, it is possible to improve regulator performance if it has a flow control valve. When doing these exercises it is normal, especially the first times, to significantly increase air consumption, so we suggest you frequently monitor your gauge to avoid unpleasant surprises. With experience, consumption will become normal and then even decrease slightly when you get used to breathing with your nose. After carrying out these few exercises we can now use our new mask to its fullest capabilities. Enjoying the sight of the marine world with greatly improved vision and being able to breathe in an unusual way for us divers gives us the joy of an exciting new discovery. And we thought we had done it all underwater!!! Rel 5.0 OCEANREEF September 2010

23 Special options Of the various full face mask models available on the market, one allows for the use of two simultaneously attached regulators. What are the advantages of such a possibility? Out-of-the-ordinary dives, like those done in polluted waters and penetration into deep caves or shipwrecks, require special capabilities that go far beyond the safety limits recommended by most diving schools. However, professionals and divers of technical organizations need to be able to change air sources without having to remove the mouthpiece, partly because surrounding conditions prohibit it, and partly because they are often working without a partner, either due to choice or necessity. For these divers it could be useful to be able to isolate the malfunctioning regulator and use the back-up by simply opening a valve. However, all of this is purely theoretical for the recreational diver. A dive within the recommended limits, under favorable conditions and with proper planning, has never forced anyone to replace the regulator in his/her mouth with a back-up, unless he wanted to try doing it as a training exercise. Who then, might need the alternative air source (AAS) of a diver with a full face mask? Certainly, his/her diving partner. Therefore, even if we use a full face mask and can use two regulators simultaneously, we have our alternative source available, as we were taught, for our partner in case of necessity. Communicating with the full face mask As we have mentioned previously, the full face mask offers the diver the possibility of using underwater communication systems. Almost all the masks on the market are designed to accept these systems and their universal attachments, permitting the user to choose a system independently of the choice of mask model. We shall discuss underwater communication systems and their characteristics later on. What I want to say now is that when using a full face mask it is possible to communicate verbally with your diving partner even without using a communication system. How is this possible? Try it. Go to within a couple of inches of your diving partner's ear and pronounce your words well. Communication will be efficient if your tone of voice is loud and clear. Of course, at a distance of 4 or more inches it becomes impossible to hear. It's not much, but short of buying an underwater communicator it's better than hand signals. It's easy enough to explain why we can hear words in this manner. When we emit sounds from the mouth, we cause the air to vibrate, which in turn makes the visor vibrate and transmit the sound. Rel 5.0 OCEANREEF September 2010