Doubles Manifold

[captain]

You usually can find the USD manifold on ebay for less than $100. New I believe it is near $800. I have one mounted on 72's.

 

[Akimbo]

http://www.aqualung.com/militaryandprofessional/product_information/j-k-twin_manual_07-07.pdf

You're right, I stand corrected. We had some solid manifolded doubles without reserves in the diving locker at Submarine Development I in the in the 1970s, but now that I think of it they weren't standard inventory. They were probably left over from some of the semi-closed prototypes that didn't work out. Sorry.

On closer inspection, the XS-Scuba manifold probably isn't made from the same forging tooling as Aqualung's. Makes you wonder that their motivation is. You would think that they have to be looking at a larger market than vintage double hose and Kraken users???

 

[rhwestfall]

Very surprised to see it with no reserve (j-valve). Military and OSHA require reserve, and likely the 99% using it... It does have port plugs on each end, and I am wondering f it can be fitted that way?

 

[Akimbo]

... It does have port plugs on each end, and I am wondering f it can be fitted that way?

My “best guess” is no. The Aqualung manifold has an enlarged diameter on the forging to accommodate the reserve mechanism and XS-Scuba would likely release a reserve model at the same time if they had one.

I think that the great majority of divers experienced with the rotating lever reserve find it seriously lacking anyway. Are you sure that OSHA (Occupational Safety & Health Administration in the US) requires a “reserve” or are isolation manifolds on doubles accepted?

It is ironic that the original Cousteau-Gagnan triples had a very effective hard reserve. One of their cylinders had a post valve that was closed during the dive giving them about a one-third reserve when they opened it to equalize.

 

[rhwestfall]

So I have been told, they require something to alert lower pressure that works in "limited visibility" if using a tank supplied air source. I don't have a set of regulations handy as my employer wants us immune from "dictating" safety that the contractor is required to know and obey...

 

[Akimbo]

So I have been told, they require something to alert lower pressure that works in "limited visibility" if using a tank supplied air source...

I use Progressive Equalization for that reason and so I don’t have to be so obsessive at checking my SPG or computer. It is pretty tuff to miss sucking a vacuum no matter how distracted you are.

The trouble is that standard isolation manifold would be miserable for a double hose — and wearing them valve-down would be virtually impossible. It really wouldn’t be that difficult to build a valve-down set of doubles that supports a double-hose for progressive equalization. Two rebreather valves, modify a couple DIN plugs, an off-the shelf yoke adapter, a few fittings, tubing, and some silver-brazing would do it.

 

[John C. Ratliff]

Very surprised to see it with no reserve (j-valve). Military and OSHA require reserve, and likely the 99% using it... It does have port plugs on each end, and I am wondering f it can be fitted that way?

rhwestfall,

OSHA does not "require" a J-valve. Here's what the regulations from Oregon OSHA, which are adopted verbatum from Federal OSHA (and much more clearly numbered) states:

(c) Procedures.(1) A standby diver shall be available while a diver is in the water.
(2) A diver shall be line-tended from the surface, or accompanied by another diver in the
water in continuous visual contact during the diving operations.
(3) A diver shall be stationed at the underwater point of entry when diving is conducted in
enclosed or physically confining spaces.
(4) A diver-carried reserve breathing gas supply shall be provided for each diver
consisting of:
(i) A manual reserve (J valve); or
(ii) An independent reserve cylinder with a separate regulator or connected to the
underwater breathing apparatus.
(5) The valve of the reserve breathing gas supply shall be in the closed position prior to
the dive.
Stat. Auth.: ORS 654.025(2) and 656.726(4).
Stats. Implemented: ORS 654.001 through 654.295.
Hist: OR-OSHA Admin. Order 5-1993, f. 5/3/93, ef. 6/1/93.
http://www.orosha.org/pdf/rules/division_2/div2_t.pdf#page=29

Note that a pony bottle would satisfy this requirement. Federal OSHA explained their rule in the following manner:

7. Emergency Egress

(a) Bail-out system. The proposed condition would require employers to equip their divers with a reliable emergency-egress system (i.e., a "bail-out system") for emergencies involving SCUBA malfunctions that endanger diver health and safety (e.g., high CO2 levels). The bail-out system must contain a separate supply of breathing gas, which may include air, and provide the breathing gas to the second stage of the SCUBA regulator. OSHA is including this condition in the final standard as proposed because the bail-out system enables divers to shift to a known, safe, and immediately available breathing gas, and to terminate the dive safely whenever a CO2-related problem or other emergency occurs.

(b) Alternative systems. In the proposal, this condition allowed for alternatives to bail-out systems for use with open-circuit SCUBA and semi-closed-circuit or closed-circuit rebreathers. Such an alternative system would provide the diver with a reserve supply of breathing air or gas mixture. When a diver uses open-circuit SCUBA with a nitrox breathing-gas mixture, the alternative system permits employers to use the emergency-egress procedure (i.e., reserve breathing-gas supplies) specified for open-circuit SCUBA by paragraph (c)(4) of § 1910.424 instead of a separate bail-out breathing-gas system.(8) For semi-closed-circuit and closed-circuit rebreathers, such an alternative system would be configured so that the second stage of the regulator connects to a reserve supply of emergency breathing gas.

The Agency is adopting the condition in the final rule as proposed. In this regard, paragraph (c)(4) of § 1910.424 already recognizes the safety afforded to divers by the alternative system used for air- supplied open-circuit SCUBA diving operations. Therefore, OSHA concludes that this alternative system will provide a similar level of protection to divers who use open-circuit SCUBA supplied with nitrox breathing-gas mixtures. In extending this alternative system to semi-closed-circuit and closed- circuit rebreathers, OSHA believes that any bail-out system that allows divers to access a secondary source of sufficient quantities of emergency breathing gas will provide them with the requisite level of protection during emergency escape. Examples of a secondary source of emergency breathing gas include an inflator-regulator system or a manual reserve activated by a valve maintained in the closed position until needed (as permitted for air-supplied open-circuit SCUBA under § 1910.424(c)(4)(i) and (c)(5)).

(c) Safety requirements. This proposed condition provided that employers rely on rebreather manufacturers to specify the necessary capacity for a bail-out system because these manufacturers are in the best position to make this determination. A rebreather manufacturer can determine this capacity based on critical diving parameters (e.g., depth of dive and breathing rate) provided by the employer.

The Agency is including this condition in the final rule as proposed because it ensures that the bail-out system used by divers, whether it is a separate bail-out system or an alternative bail-out system built into the breathing equipment, will function appropriately when needed by the diver for emergency egress. A properly functioning bail-out system will enable the diver to terminate the dive and make a safe and controlled ascent to the surface under emergency conditions, thereby preventing over-pressurization of the lungs associated with AGE.
https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=FEDERAL_REGISTER&p_id=18073

As you can see, the Federal OSHA explanation allows several alternatives, but "allows" the J-reserve (if in the "up" position). Note also that the OSHA personnel who wrote this did not have a real good idea of what they were writing (e.i., the reference to "CO2", possibly in a FFM or rather than carbon monoxide, and the sentence about "...Examples of a secondary source of emergency breathing gas include an inflator-regulator system or a manual reserve activated by a valve maintained in the closed position until needed...").

SeaRat
John C. Ratliff, CSP, CIH, MSPH
(CSP: Certified Safety Professional; CIH: Certified Industrial Hygienist)