Monday, September 19, 2011

How much weight will one of your caskets hold?

We get this question often.  People are curious to know how much weight one of our simple pine caskets can carry. Funeral directors need to be assured that one of our caskets will not end in a terribly awkward moment for the family and a liability situation for the funeral home.  Families are curious if the larger-than-normal interior dimensions of our Northwoods pine caskets might accommodate plus-sized family members (casket inside dimensions are 78L x 24W x 18D inches).

Most commercial caskets are tested to carry 500 lbs.  Previously, we tested our casket to 600 lbs with bags of sand.  This time we took a more scientific approach and documented the test with photographs and a video.  We planned to load the casket until it fails and measured out 1000 lbs. of patio blocks for the job.

Casket Load Test Setup
Four stands support the casket at the handles.
We chose to simulate the load conditions for a casket whereby only 4 pallbearers carry the casket with handles on corners.  In our experience as pallbearers, the smallest cousins carry the middle handles--and don't carry much of the load leaving the heavy lifting to the larger cousins at the ends.  We built 4 wooden stands to support the casket about 8 inches from the floor.  This way, the full weight of the casket rests on 4 of the cotton rope handles.

1000 lbs of patio bricks ready.
We weighed several patio blocks finding the larger blocks to be about 9.25 lbs and the smaller blocks just over 6 lbs.  We stacked the blocks in 10 groups of 100 lbs each.  A total load of 1000 lbs is ready to load into the casket.

Casket Preparation
The casket is our standard Northwoods Pine Casket.  The casket was previously assembled with glue and screws and the screws were removed.  The casket is 100% metal-free and suitable for burial in conventional cemeteries or green/natural burial cemeteries as well as cremation.  The tongue and groove board construction provides optimal strength without building up stresses in the sides and floor due to changes in humidity and temperature.  The rib and dado (groove) construction design provides significant strength.  The entire floor rests in a dado cut into each of the 4 sides.  The entire load on the floor is transferred to the rope handles through the 10 vertical ribs held in place with Elmer's Wood glue.

Loading to 300 lbs
300 lbs in the casket.
We started with a distributed load of 300 lbs.  We let the casket sit for a few minutes listening and watching for stresses in the wood.  The casket floor did not deflect or sag from the weight.  The 4 rope handles supporting the load were tight, but that was the only noticeable change.

Loading to 500 lbs
500 lbs in the casket.
With 500 lbs of patio bricks stacked in the casket, our Northwoods pine casket now contains the same weight with which most commercial caskets are tested.  The rope handles are tight, but there is no noticeable deflection in any of the wood sides or floor.  The room is silent and absent from the creaking, popping, or splintering sounds of stressed wood.

Loading to 700 lbs
700 lbs in the casket
When we started this test, we planned to load the casket to the point of catastrophic failure ready to learn something about the weakest part of our design.  We carefully positioned our cameras and video cameras preparing to catch the moment of collapse on film.  Now we carefully place another 200 lbs of patio bricks in the casket.  We are careful to keep our toes clear from the underside of the casket as the ropes stretch on the 4 wooden stands.  With 700 lbs in the casket, we are pleased in the continued silence.  No sounds of stressed wood can be heard.  No popping glue joints.  We have a look at the underside of the casket and the floor is just beginning to sag--a quarter inch at the most.  This test is proving to be uneventful.

Loading to 1000 lbs
1000 lbs in the casket.
We reset our cameras and video and quickly load another 300 lbs in the casket.  Again listening carefully for that first pop or splinter and looking for signs of failure at every corner of the casket and in the floor, but there are no sounds or visual indications the casket will fail.  We let the casket sit with 1000 lbs in it for several minutes as we take photos and film the video.  The floor is sagging a quarter inch, but with no sign of failure.  The upper sides are bowing in as much as a quarter inch, but no indication the casket will fail.  We have loaded our casket with two times the industry standard and not so much as even one pop, creak, or splinter!

How about 1000 lbs + Jonas + Dave = 1400 lbs!
1400 lbs in the casket.
At this point we have let 1000 lbs sit for a good 15 minutes without so much as one creak or splinter coming from the casket.  Mixed emotions of accomplishment and disappointment fill the room.  We started the day fully expecting to destroy one of our caskets and capture the moment on film--learning something about our design and the properties of wood under stress.  We proceed to seat both Dave and myself on top of the patio bricks adding another 400 lbs to the casket!

With 1400 lbs in the casket, we finally hear a pop!  The pop is the sound of stress somewhere in the wood, but after a thorough inspection we find no sign of failure at any glue joint or any piece of wood.  With 1400 lbs in the casket and no failure, we are finally satisfied.  I am quite certain that the casket might fail at 2000 lbs, but I'm not sure what we would learn from that.  I think at 1400 lbs, we've answered the question, "How much can a Northwoods casket support?" and laid this topic to rest.

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