I forgot to mention that I am a student and that the book I am reading is in English which isn't my native language.

daer, that is fine as long as you feel you fully understand what you have read.  speed readers never speed read anything of any substance nor do they do more than remember facts, which is different than understanding.

think of it this way, you're looking at a math formula, a math formula is maybe a sentence long, but it might take a week to fully understand, you may have to do other research, an Immanuel Kant walk around the block etc...

keep reading!

Your speed sounds ok for a non-native English speaker.  Like Max says, understanding what you read is key over speed at this point.  Speed will come with continued effort.

I'm seeing a lot of new college graduates working in our office that don't appear to be able to read or write at a college level.  They are native-born and educated in the USA.

I think it depends on why you're asking the question.  Since you posted the question in the "Academia" category, I'm guessing you're a student.  If you're studying in an English-based program this might pose a problem - or maybe not.  It depends on how much assigned reading is typical in your program, and on how much flexibility you have in choosing a course load that requires more or less reading.

I know people who have gotten all the way through architecture school without having to read much more than a few pages of handouts per week.  If you have the option and predilection to take a lot of courses that are less book-based and more about skills (software, drawing, photography, welding, whatever) then you might be able to cut down your reading requirements enough that it's not a big problem.

On the other hand, in my M.Arch program I usually had about 300 pages of assigned reading per week on top of studio work.  We had a lot of reading assignments by our primary studio professors, plus a lot of required theory courses with reading/writing requirements.  An average person reading in their native language reads about one page per 2 minutes, so 30 pages per hour - so 300 pages took about 10 hours per week, which was doable, but at your rate that amount of reading would take you 50 hours, which is a lot less doable on top of class time, studio work, etc..  Of course one might expect that you'd get faster with practice.

Once you're out of school and working in firms I don't think this will pose much of a problem.  There is some reading required in some roles in architecture firms some of the time, but not enough to cause frequent problems for you.  

I have decided that I want to enhance my technical skills, therefore I plan on reading several books on construction, building services etc. The important thing for me is to understand the information presented in the books and gradually build up on my knowledge. While reading, I underline the most important information and then revise that twice. The reason I posted this thread was to understand whether everyone else also experiences slow reading speeds when reading technical information.

Tying to read through ARE study material has reminded me how much slower I am when reading technical or theory stuff than a good book.

Not a fair comparison imo. What about your speed when reading theoretical materials?

It isn't fast but reading is for meaning, not speed. Slow is good if you are deep reading and understanding and integrating it. What do you feel you are you slow at? Just generally? Or Are you getting stuck on some difficult things? Just like when you are taking a test and come across something you are struggling with, it is better to move on because something later will likely help you with what you didn't get before. Then you can revisit a difficult part and get it then rather than getting slowed down. I do it all the time when reading technical stuff. And yes, all text is not equal, more demanding text slows everyone down.

Since you're reading this info for your own edification and not to meet any particular deadline, I don't think your reading speed really matters.  The important thing is that you're understanding it, so don't worry about it.  That said, the best way to understand construction is to get some construction experience, if possible.  Even a little will help forever in this field.