cmu insulation

huangyhg

cmu insulation
i have an architect who says that he has worked with other engineers who do not require the removal of the cell insulation in the masonry cells that are to be reinforced and grouted.  i do not agree with this but i am wondering what other people do?
if the reinforcing is not grouted in place, it does not reinforce the masonry wall.  
grout and insulation are usually not compatible, but there are ways that may work depending on the insulation system the architect has selected.
there is a method that i have seen a few times (one was on a prison job).
it involves the use of a proptiety polystyrene insert, since bulk insulation (perlite, vermiculite, foam beads) or foamed in place would not work. this sytem was not developed for grouted masonry, but it can be used with a minimu of extra effort.
the t-shaped (horizontal view) insert has an upper portion that provides insulation in the reuced height web area. the block for this is a nominal 8" high and 16" long cmu with two webs (not the traditional 3 webs) at 8" o.c. to provide larger, true, straight, aligned  vertical cavities. the two webs are reduced in height about 2" to provide a space for insulation and minimize the heat loss through the webs. the recess is radiused and contoured (instead of a squre cut-out) to reduce stress concentrations.
the inserts are placed against one face shell (depending which side is the tension face) with the grout and steel in the remaining portion of the core. depending on the wall thickness and the thickness of the insert (several thicknesses up to 4" are possible), you can have a problem with the aci 530 minimum grout space dimensions for an 8" wall with 4" thick inserts. the minimum grout space dimension requirements usually not a factor for the 10" or 12" thick walls.
because the cores align and the inserts are placed as the wall is constructed, if desired, mortar can be placed on the top of the open areas of the recessed web to create a closed cell for partial grouting.
i have seen test reports on the grouted wall sections, so i imagine they are available.
the insulation system is enerblock or enerblok and there is a .com site.
dick
insulation in void cells has very little insulation value for the wall system as a whole.  outsulation is beat.
i read the post as saying that the cmu wall is under-reinforced presently and needs to be upgraded by adding vertical grout and reinforcing.  that being said, i would specify that any insulation in any of the cells to be grouted would have to be removed prior to grouting.  i would worry about the insulation compromising the strength of the grout, and hence the wall, if it were not removed.
outsulation...really!
mike mccann
mmc engineering
steel -
mike brought up a very good point questioning whether this is a new design for construction or a modification to an existing structure? that is critical, since i read it as being a new structure.
civilperson -
insulating the cores is not as good as "outsulation", (on the exterior surface) which in superior to "insulation" (on the interior surface) on a long term basis, but is this an improvement.
filling cores is not as effective as rigid insulation but it can make a big difference because of the square footage of of exterior walls on some buildings. whatever you do, don't make the common mistake of filling all the cores with grout.
proper insulation in the cores can reduce the heat loss by 20% to 40%, depending on whether normal weight or lightweight block are used. there is more benefit filling the more costly lightweight block than filling normal weight block. both can reach the same strengths, except when you go beyond 4500 psi unit compressive strength.
if this is a new structure, there may be enough improvement to keep the structure withing the energy requirement. insulation in the unreinforced cores of the wall is certainly an option/improvemnt if a new energy analysis and design the option.
dick

this is a new wall with a rigid styrofoam insulation inside the blocks.  the architect received a call from the site about removing the insulation and was unable to reach me so he told them they could keep the insulation in the cells of the block.  this was based off his experience with 2 other engineers he has worked with before.  i was able to straighten everything out shortly after so it wasn't a big deal.
i was just wondering what other people do.  this particular wall is a 12" exterior masonry wall 21' high with reinforcing at 40" o.c.

it all depends on what kind of inserts were used. the old style are just pieces of styrofoam to will the cores without any regard to continuity at the joints. that is the problem for the architect that seleceted to type of insulating system. you should get test results for insulated grouted walls constructed with the type of insert used.
most inserts are not meant for grouted construction and do not have continuity of insulation at the head and bed joints of the masonry.
usually, for partially reinforced grouted walls, i have seen grout only in the reinforced cells if there is a totally vertical continuous grout cell. it helps if the correct shape of block is used (insulated or not) if you really want to control the grout placement. most engineers miss the block shape and core alignment imortance. this allows the option of further insulating the remaining cells if you have 12" units. extra grouted cells is minimally effective for flexure and you probably have more than enough vertical strength (f'm).
heat conduction tests on cmu walls having cells filled with insulation shows very little improvement over void cells due to the webs and ends being heat transmitters. 20-40% less heat loss is not believable.  
civilperson  - look at the real and more recent tests using modern units. there are far too many old tests in the research libraries and also some very suspect labs that know how to skew the results.
these are all the lab short term tests under steady state conditions. the dynamic cycling tests provide more realistic results. that is why there is a feeble atempt to provide a "mass correction factor" aplicable for use by professionals. even the r-19 pink stuff in a wall will only give you an effective r-11 in some stud walls if you are into the r-value, u-value concepts that are not given high marks in many countries.
granted, filling the cores will never be able to honestly produce the advertising of the pink pather, but there are gains of up to 40%, which can be important considering the square footing.
i have spec'd insulation in cells to be grouted.  i did get copies of tests done on the block before i bought into it.  i still am a bit skeptical, but my boss had used it before and assured me it was ok.  i can't re