remove header & footer for specific page

[iEscapedVim]

Hi

I am working on this theme/template for our hosting site, and I came across a little hurdle, first being smarty its self as not only I was new to php and doing myself a fun project this was kind of something that spoiled my mood a bit anyway not here to rant about that. I want to know how can I disable or something so that they don't load for current pages generally the error pages such `error/page_not_found.tpl`, `error/internal_error.tpl` and `error/unknown-routepath.tpl` for example something like 

if (!is_page_not_found()) {
    include 'header.php';
}

I wanna know what needs to be done to achieve something like..