tcpdf transform 01EAA to blank

[corpplus]

I am using the open source class TCPDF to generate a pdf file, I have to output the list of items in my database, each item has a code like : 01BAA , 01BAB , A17B ...

//Some code before
foreach($sites_direction_ids as $sites_direction_id)
{
$html .= '
<tr class="tr_site">
<td>'.$site["site_direction_code"].'</td>
<td>'.$site["full_site_loc"].'</td>
<td>'.$site["site_direction"].'</td>
<td>'.$_format->size($site["width"],$site["height"]).'</td>
<td>'.$duration.'</td>
<td>$'.$_format->_number($rate_card).'</td>
<td>'.$_format->_number($discount).' %</td>
<td align="center">$'.$_format->_number($after_discount).'</td>
<td align="center">$'.$_format->_number($direction_total).'</td>
</tr>
; 
}
//Some code after

The following $site["site_direction_code"] contains the code, when the code is from 4 digits, it's displayed normally, but if it's 5 digits like 01EAA, the tcpdf class transform it to a break line and make a big space between rows, so how i want to tell the class to display the code as it's without execute it to some special meaning?