INSULATION CONSTRUCTION METHODS FOR HIGH ALTITUDE
AS WE GEAR UP FOR OUR RETURN TO HIGH ALTITUDE WINTER CLIMBING IN TIBET WE HAVE BEEN REAPRAISING THE INSULATION OPTIONS OUR CLIMBERS ARE WEARING. THIS IS POINT OF REAL INNOVATION TO THE DEGREE WE HAVE ABANDONED OUR EARLIER RECOMMENDATIONS, AND FOUND LIGHTER, MORE VERSATILE AND WARMER OPTIONS BY COMBINING VARIOUS METHODS OF CONSTRUCTION.
WE ARE NOT THE FIRST TO DO THIS OF COURSE – WITH THE NORTH FACE, MARMOT AND PHD HAVING SPECIFIC COMBINATIONS BOUGHT TO THE 8000m MARKET – BUT WE ARE PERHAPS THE ONLY ONES ADVOCATING CERTAIN COMBINATIONS AIMED SPECIFICALLY AT SELF-SUPPORTED ASCENTS AROUND 6000 TO 7000m.
ON INDUSTRIAL TRIPS YOU CAN TRY ALMOST ANYTHING AS THE LOGISTICS IS IN PLACE TO TRANSPORT IT ALL, AND THE STYLE OF CLIMBING IS PREDICTABLE, EVEN AND BASIC. ON OUR TRIPS WE NEED TO BE MORE ADAPTABLE AND GEARED FOR THE RIGORS OF TECHNICAL CLIMBING, WHICH MEANS GETTING MORE FROM OUR EQUIPMENT WHICH MEANS BETTER SYSTEMS. THIS IS SEEN ARGUABLY NOWHERE MORE LUCIDLY THAN WHAT WE USE TO STAY WARM.
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CONSTRUCTION METHODS DETERMINE THE WAY INSULATION WORKS, AS WELL AS COST AND THE TYPE OF INSULATION USED. HOW INSULATION IS CONSTRUCTED MATTERS JUST AS MUCH AS WHAT SORT IT IS, AND CERTAIN JOBS ARE DONE BETTER WITH DIFFERENT WAYS OF MANIPULATING IT.
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DOUBLE WALL
ALSO CALLED ‘BOX CONSTRUCTION’ THIS IS TWO FACES OF FABRIC WITH SHELVES OF SCRIM IN BETWEEN, THAT IS FILLED WITH INSULATION AND HAS NO COLD SPOTS WHERE THE FACINGS ARE PINCHED TOGETHER. THE FACINGS ARE CUT WITH DIFFERENTIAL SIZES SO THE INSULATION LOFTS BETWEEN THEM.
THIS IS EXPENSIVE BECAUSE IT TAKES A LOT OF EXTRA WORK, BUT IT IS ALSO AMONG THE BEST WAYS TO GET THE FULL POTENTIAL OUT OF HIGH FILL POWER DOWN. THIS SORT OF CONSTRUCTION CAN ADD NEARLY HALF TO WHAT A GARMENT COSTS, BUT IS ALSO A WAY TO GET THE MOST OUT OF ANY DOWN.
THE TRADE OFF IS THAT THIS IS BY FAR THE HEAVIEST, HAVING THE MOST FABRIC USED, AROUND DOUBLE OF SOME OTHER METHODS. THERE IS A DEGREE OF TRADE OFF AS IT ALLOWS ANY INSULATED FILL TO LOFT OPTIMALLY AND SO IS THE WARMEST, BUT IT STILL HAS THE MOST MATERIAL WHICH IS WHERE A GARMENTS WEIGHT COMES FROM.
BEST USED FOR FULL CONDITIONS OUTER LAYERS, WHETHER A SINGLE LAYER OR PART OF SEVERAL, BECAUSE THIS METHOD HAS THE MOST PROTECTION.
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REGULAR SEWN THROUGH
THIS IS WHAT IT SOUNDS LIKE; TWO LAYERS OF FACING FABRIC STITCHED DIRECTLY TO EACH OTHER WITH INSULATION IN THE SPACES BETWEEN. THIS IS THE CHEAPEST WAY TO SECURE LOOSE INSULATION LIKE DOWN AND THERMOPLUME, AND THE SPACES CAN BE SQUARE, V-SHAPED, HORIZONTAL, VERTICAL, DIAGONAL AND NON-REGULAR, BUT ALL SUFFER COLD SPOTS TO SOME DEGREE THOUGH THIS CAN BE USED AS A POSITIVE THING.
THE VOLUME OF THE INSULATION SPACES DIFFERS WIDELY, FROM LARGE POCKETS THAT HOLD A LOT TO LOTS OF SKINNY ONES. LARGE ONES CAN BE BILLOWED UP, LIKE YOU DO WITH A SLEEPING BAG, TO REDISTRIBUTE THE FILLING AND EVEN MANIPULATE IT INTENTIONALLY (LIKE OVER THE SHOULDERS AND AROUND CUFFS), WHICH IS NECESSARY AS THE FILLING HAS MORE SPACE TO SETTLE IN, BUT SMALL ONES HOLD THE FILLING TIGHT THOUGH HAVE MORE COLD AREA.
SOME SEWN THROUGH TUBES ARE DIAGONAL OR V-SHAPED, THE IDEA IS THAT THE FILLING WILL OCCUPY A PREDICTABLE SPACE INSIDE ITS TUBE OF FABRIC AS IT SETTLES, SO RATHER THAN THAT BEING A SERIES OF HORIZONTAL OR VERTICAL COLD SPOTS, THAT ARE OFFSET BY BEING DIAGONAL. IF THE LOWER 20cm OF A BAFFLE IS WHAT THE DOWN SETTLES INTO, BY STACKING THEM DIAGONALLY THE TOP OF EACH BAFFLE IS NOT A DEFINED LINE THAT GETS COLD. SOME DESIGNS FURTHER MANIPULATE THE WAY THE INSULATION COLLECTS BY SEWING ACROSS THE TUBES TO FURTHER REDUCE DRIFT AND THE UPPERMOST PART OF THE DIAGONALS FROM EMPTYING.
BEST USED FOR INNER LAYERS THAT ARE NOT YOUR PRIMARY INSULATION, WHICH MAY NEED TO SHED SOME HEAT. THIS INCLUDES FOR SLEEPING IN, WHERE THE GENERAL ENVIRONMENT IS WARMED, SO THE LAYER NEXT TO YOU IS THERE JUST THERE TO STABILIZE IT.
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DIFFERENTIAL CUT SEWN THROUGH
THIS IS SEWN THROUGH, BUT WHERE THE TWO FACINGS ARE OF DIFFERENT CUTS, LARGER AND TO-SIZE. THIS LETS THE SMALLER, TO-SIZE SIDE FORM THE BASE OF THE GARMENT, AND THE OTHER SIZE BILLOWS OUTWARDS FORMING ‘SPACE ‘PSEUDO-BAFFLES’ TO BE FILLED WITH INSULATION. THERE ARE STILL COLD SPOTS WHERE IT’S STITCHED THROUGH, BUT THEY ARE LARGELY FILLED IN WITH THE OUTWARD LOFT WHERE THE PSEUDO-BAFFLES SQUEEZE TOGETHER.
SOMETIMES CALLED ‘3D BAFFLES’ THIS IS LIKE A POOR MANS DYNAMIC BAFFLES (SEE BELOW), THAT ALLOWS SOME HEAT TO BE RELEASED WHILST MAINTAINING FULL LOFT, BUT NOT NEARLY AS MUCH BECAUSE LESS SINGLE-LAYERED AREA IS EXPOSED. THOUGH THE WARMEST METHOD AFTER DOUBLE WALLED BUT CAN BE TOO COOL FOR OUTER LAYERS FOR THE COLDEST CONDITIONS WHEN IT MATTERS MOST.
BEST USE HERE IS IN MIDLAYERS, ESPECIALLY PANTS WHERE IT ARTICULATES WELL AND NEEDS LESS VENTING THAN DOUBLE WALLED ONES. THIS COULD EXTEND TO USE AS AN OUTER LAYER FOR ASCENTS THAT ARE ALWAYS MOVING, WHERE WEIGHT AND HEAT BUILD UP A REAL FACTORS, BUT ANY LONG BELAYS OR HIGH WIND WOULD FIND THE METHODS FAILINGS.
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DYNAMIC BAFFLES
WE DON’T KNOW WHAT ELSE TO CALL THIS METHOD, WHICH IS A PROGRESSION OF THE DIFFERENTIAL AND DOUBLE WALL STYLES. IN THIS CASE TUBES OR CUBES OF INSULATION ARE SEWN TO A SINGLE FACING, THAT SQUEEZE TOGETHER AS A CONTINUOUS LAYER WHEN STATIONARY BUT BELLOW CONCERTINA-LIKE WITH MOVEMENT TO DUMP SOME HEAT.
IN MOST CASES THE FACING IS A WEATHERPROOF/BREATHABLE FABRIC, ALLOWING MOISTURE TO RELEASE LIKE A SOFTSHELL. THIS METHOD GENERATES A LOT OF INSIDE WARMTH WHICH GIVES A HIGH PRESSURE RATIO FOR PUSHING MOISTURE OUT, AND REALLY CAN ACT LIKE AN INSULATED, BREATHABLE SHELL/MIDLAYER COMBINATION.
BEST USED AS INNER LAYERS FOR SERIOUS COLD, WHERE THE LAYER NEEDS TO COVER A WIDE RANGE OF USE FROM HIGH EXERTION TO DEEP STASIS – WHICH IS EFFECTIVELY THE DEFINITION OF ALPINE CLIMBING.
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NON-REGULAR
THIS IS THE SEWN THROUGH BUT THE SPACES THE INSULATION INHABITS ARE NOT JUST STRAIGHT, REGULAR TUBES, USUALLY BEING COMPLEX PATTERNS PURPORTED TO ALLOW THE INSULATION TO LOFT BETTER. BECAUSE INSULATION LIKE DOWN SETTLES WITH GRAVITY TO THE BOTTOM OF THE SPACES, AND BECAUSE REGULAR SEWN LINES CREATE REGULAR COLD SPOTS, THIS METHOD IS A WAY TO REDUCE THE OVERALL SURFACE AREA OF SEWN THROUGH COLD SPOTS.
THIS IS THE BEST NON-3D BAFFLED CONSTRUCTION THAT GETS THE MOST OUT OF INSULATION LOFT WITH THE MINIMUM OF CONSTRUCTION COMPLEXITY AND WEIGHT, SO A WAY TO REEL IN COSTS A BIT. IT WORKS BEST FOR INNER LAYERS WHEN COMBINED WITH VERY HIGH QUALITY DOWN, AND WHERE IT WILL BE EITHER VENTED EASILY OR ALWAYS UNDER A TOP LAYER ON COLD AND SLOW ROUTES.
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UNBAFFLED
SYNTHETIC SHEET INSULATION IS OFTEN WITHOUT BAFFLES, BEING SEWN IN PLACE ALONG WITH THE PANELS OF THE GARMENT. THIS FORMS A TRUELY CONTINUOUS LAYER WITHOUT COLD SPOTS, AND WHEN COMBINED WITH A DIFFERENTIAL INNER AND OUTFACING IS HOW THE WARMEST SYNTHETIC STUFF IS MADE.
SOMETIMES THIS METHOD IS FOUND HYBRIDIZED WITH DOWN, AS AN OUTER LAYER TO PROTECT AGAINST MOISTURE, WHICH WORKS WELL IN ITS WAY BUT IS HEAVY FOR THE INSULATION VALUE. SYNTHETIC INSULATIONS WATER REPELLENT PROPERTIES THOUGH MEAN IT MUST BE WELL VENTED, AND MAKES IT HARD TO FIT INTO A HIGH ALTITUDE SYSTEM WHERE EXTERNAL MOISTURE ISN’T A HUGE ISSUE.
WHERE THIS SHINES, WHEN DONE WELL WITH A LARGE LOFT OF FILLING AS AN OUTER LAYER, IS AS A BIVY JACKET FOR ASCENTS USING SNOW HOLES, OPEN BIVIES OR THAT ARE NON-STOP AND EXPOSED. THIS IS THE HIGHEST LEVEL OF PROTECTIVE INSULATION YOU CAN GET, BUT JACKETS THAT TRULY FIT THIS NICHE ARE RARE. THIS IS A LEVEL UP FROM THE COMMON ‘BELAY’ JACKET – WHICH IS GREAT FOR LOWER OR WARMER STUFF – WITH THE BEST EXAMPLE WE KNOW BEING THE OBSCURE AGLOW JACKET ONLY FROM THE NORTH FACES JAPANESE MARKET.
THIS WORKS BEST FOR BELAY PANTS, BEING HIGHLY PROTECTIVE AND MUCH LESS COMPROMISED IF SLASHED OPEN BY CRAMPONS OR TORN ON ROCK, OR FOR OUTER JACKETS FOR ROUTES THAT ARE WARMER, WHEN COMBINED WITH A GOOD MIDLAYER.
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SLEEPING BAGS
AS SLEEPING IS ENTIRELY A STATIONARY THING, THE BAGS CONSTRUCTION NEEDS TO REFLECT THAT. HIGH ALTITUDE IS NOT THE PLACE FOR REGULAR SEWN THROUGH DESIGNS*, WITH THE EXCEPTION OF DIFFERENTIAL BAFFLES, WHERE THE CURVED CROSS SECTION OF A BAG KEEPS THE FILLED TUBES PUSHED TOGETHER. WHEN THE BAFFLES ARE ARRANGED VERTICALLY THIS ALMOST ACHEIVES WHAT DOUBLE WALL DOES AT A BIT LESS WEIGHT AND COST.
COMBINED WITH THE LAYERS YOU WEAR INSIDE THE BAG AND A BAG THAT IS SIZED TO ALLOW THEM TO LOFT, THE RIGHT BAFFLING ACROSS THE SYSTEM CREATES A VERY EFFICIENT INTEGRATED RESULT. COMBINED THIS WEIGHS ABOUT 2/3 OF WHAT IS USUALLY USED IN SUCH CONDITIONS, AND IS MUCH EASIER TO MANAGE, MAKING IT A MAJOR LEAP FOR STEEP ROUTES WITH TINY CAMPS.
*THE ONE CAVEAT HERE IS FOR DOUBLE BAG SYSTEMS, WHERE A VERY LIGHT SEWN THROUGH BAG USED INSIDE A DOUBLE-WALLED OR DIFFERENTIAL BAFFLED BAG IS EFFECTIVE. THIS IS THE LIGHTEST SOLUTION
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IN COMBINATION
IF YOU JUST WANT TO BE WARM THEN A SINGLE DOUBLE-WALLED LAYER WORKS, AS GENERAGTIONS OF ONE PIECE SUITS ATTESTS. BUT IF YOU WANT TO BE ABLE TO PERFORM IN ALPINE STYLE WITHOUT THE LUXURY OF STOCKED CAMPS AND SUPPLY CARRIES, THEN NO SINGLE LAYER CAN COVER ALL DEMANDS.
TO TRULY TWEAK THINGS TO 6000 & 7000m WINTER STUFF – WHERE BASELINE TEMPERATURES ARE COLDER, EXTREMES ARE ABOUT THE SAME BUT MINUS THE METABOLIC ISSUES ABOVE 7500m, AND STEEP TECHNICAL CLIMBING PUSH THE DIFFERENTIAL BETWEEN ACTIVE AND STATIC – A SET OF LAYERS CAN BE DEVISED FOR THESE UNIQUE DEMANDS.
FEW INTENTIONALLY PRODUCED SYSTEMS EXIST, BUT THOSE THAT DO SUCH AS PHD, THE NORTH FACE AND MARMOT EACH HAVE THEIR OWN TAKE BASED ON IDEAS AROUND END USE, WITH ONLY THE NORTH FACE AMK SYSTEM REALLY COVERING HIGH OUTPUT, HIGH ALTITUDE, WINTER ALPINISM – BUT EVEN THAT CAN BE BETTERED. MARMOTS WARMCUBE SYSTEM IS VERY INNOVATIVE BUT STILL AIMED AT THE COMMERCIAL 8000m MARKET AS ONLY THE TOP HALF IS SYSTEMATIC. PHDS DOUBLE SUIT IS EXCEPTIONAL, BUT AGAIN IT’S AIMED AT 8000m TRIPS ALBEIT MUCH MORE VERSATILE ACROSS CONDITIONS AND CERTAINLY LIGHT, BUT IT LACKS THE BURLINESS AT ALL LEVELS (DESPITE US ASKING FOR IT…) FOR TECHNICAL CLIMBING DOWN LOW.
THE ADVANCED MOUNTAIN KIT FROM THE NORTH FACE COMES CLOSEST (ONCE YOU DISMISS THE CLUNKY ‘BASELAYERS’) BY HAVING A VERY DYNAMIC MIDLAYER – WHAT THEY CALL THEIR 50/50 SYSTEM – UNDER A FULL HIMALAYAN TOP LAYER. THE 50/50 LAYER BOTH BREATHES AND INSULATES EXCEPTIONALLY AS WELL AS PROVIDING A SOFTSHELL ELEMENT THAT REALLY DOES HANDLE MOST PRECIPITATION YOU’LL GET ABOVE 6000m AS WELL AS ABRASION AGAINST ROCK. BOTH UPPER AND LEGS HAVE THIS OPTION, MAKING FOR A TRUE INSULATED ‘ACTION SUIT’ THAT YOU CAN BOTH VENT AND LIVE IN POTENTIALLY OFF THE GLACIER, FORGOING SHELL PANTS AND MAAAAYBE EVEN A SHELL JACKET.
THIS MIDLAYER IS HARD TO BEAT, BUT IN ITS ABSENCE (IT’S EXPENSIVE & HARD TO FIND, THOUGH SERVERAL VERSIONS EXIST) IT CAN BE EQUALLED WITH GARMETS THAT USE DIFFERENTIAL AND NON-REGULAR SEWN THROUGH CONSTRUCTION. THIS IS NOT THE PLACE FOR DOUBLE-WALL OR NON-BAFFLED, WHICH IS TOO STIFLING, OR REGULAR SEWN THROUGH WHICH IS TO UNSTABLE, AND IT BENEFITS FROM THE HIGHEST QUALITY INSULATIONS THAT HAVE THE HIGHEST FILL POWER. LIKE THE AMK VERSIONS, THE IDEA IS TO LIVE IN THIS LAYER, MEANING YOU WANT IT SIMPLE, WELL FITTED, WITH A HOOD THAT COVERS MOST OF THE FACE AND INNER POCKETS FOR VITALS.
OVER THIS, THE AMK IS SO 8000m-SPECIFIC AS TO BE OVERKILL FOR 6000 TO 7000m EVEN IN WINTER, BY BEING TOO WARM AND BULKY TO CARRY. IN ITS PLACE WE GO WITH A 6000m-STYLE BELAY JACKET, WITH SEVERAL VERY GOOD ONES ABOUT FROM RAB, MHW, THE NORTH FACE, VALANDRE AND PHD. WHAT MATTERS HERE IS DOUBLE WALL CONSTRUCTION AND A SIMPLE DESIGN, THAT CLIMBS AS WELL AS IT PACKS DOWN.
ON THE LEGS (WHERE THE IDEA OF DOUBLE INSULATION SEEMS WEIRD TO SOME, BUT RECALL THAT THE BODY LOSES HEAT EVENLY EVEN IF YOU CAN’T FEEL IT) THE USUAL OPTION IS SYNTHETIC BELAY PANTS, WHICH FITS THE NEED VERY WELL SO LONG AS THE MIDLAYER IS SIZED AS SUCH. DOUBLE WALLED 6000-7000m PANTS ARE UNCOMMON, AS SUCH THINGS ARE NORMALLY AIMED SQUARE AT THE 8000m SCENE SO ARE HEAVY, BULKY AND OVER-BUILT AS YOU’D EXPECT, WITH PHD, MONTBELL AND FEATHERED FRIENDS BEING AMONG THE FEW PRODUCERS THAT SEE THE NICHE.
DOUBLE WALL CONSTRUCTION IS IMPORTANT HERE, TO GET MAXIMUM LOFT, AND TO SEAL ALL POSSIBLE AVENUES OF HEAT LOSS AS A FINAL DEFENCE FROM THE COLD. THIS IS A LAYER FOR THE COLDEST TIMES, THAT IN OUR CASE MEANS PRE-DAWN MORNINGS, LONG BELAYS AND LONG NIGHTS, POSSIBLY IN OPEN BIVIES, BUT ALSO THAT NEEDS TO GO ON AND OFF SO ABSOLUTELY MUST HAVE SIDE ZIPS.
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THE BAFFLING METHODS DESCRIBED HERE ARE WHAT MAKE SIMPLE ‘LAYERS’ WORK, IN THE SAME WAY THAT MEMBRANES AND WEAVES MAKE ALL OTHER LAYERS PERFORM. GET IT RIGHT AND YOU HAVE A TRUE ACTION SUIT FOR THE COLDEST TECHNICAL CLIMBING THAT CAN BE DONE, SOMETHING EVERY BIT A FRONTIER OF CLIMBING AS FINDING NEW PEAKS TO DO IT ON.
THESE ARE MECHANICAL ELEMENTS, THAT WHEN INTEGRATED CHANGE WHAT CLIMBING CAN BE DONE, BY REDUCING WHAT YOU NEED TO CARRY AND INCREASING THE SPECTRUM YOUR CLOTHES PERFORM ACROSS. SYSTEMS LIKE THIS, ON COLD AND STABLE PEAKS, CAN MEAN CLIMBING FOR SEVERAL DAYS WITH VERY LIGHT PACKS. THIS IS EVOLUTION AT THE SHARP END, WHERE TECHNOLOGY IS OPENING NEW POSSIBILITIE AT AN OBSERVABLE RATE, AND PUSHES TOWARDS AS YET UNAPPROACHED IDEAS ON THE WORLDS HIGHEST PEAKS.