sql server - Would a long running sql command using connection pooling cause other command using that same connection to error? -

i'm trying trouble shoot dreaded timeout expired sql error. i've noticed pattern follows.

1. user kicks off long running sql count on large table
2. error - timeout expired. timeout period elapsed prior completion of operation or server not responding.
3. followed 10 + errors - timeout expired. timeout period elapsed prior obtaining connection pool. may have occurred because pooled connections in use , max pool size reached.

third step error occurs in service first sql command web project. possible because connection broken because of #1 other connections fail? if there way exclude commands using connection pooling? thanks!

update

-i'm using ms sql 2012 , entity framework. -i've set entire db transaction level read uncommitted since don't care dirty reads

the first statement locking out of other statements @ database level. using sql server? in experience sql server locks tables in many scenarios dba reverted dirty reads--any other locking configuration caused contention.

to around problem can long running work in temporary table, , copy real table when work done.